Critical Reasoning

The current pattern of human consumption of resources, in which we rely on nonrenewable resources, for example metal ore, must eventually change. Since there is only so much metal ore available, ultimately we must either do without or turn to renewable resources to take its place.
Which one of the following is an assumption required by the argument?

(A) There are renewable resource replacements for all of the nonrenewable resources currently being consumed.
(B) We cannot indefinitely replace exhausted nonrenewable resources with other nonrenewable resources.
(C) A renewable resource cannot be exhausted by human consumption.
(D) Consumption of nonrenewable resources will not continue to increase in the future.
(E) Ultimately we cannot do without nonrenewable resources.

I found this question in the Powerscore CR Bible, Chapter: Assumption and Strengthen questions, Page number 194. On searching the Interet, I found that it happens to be an old LSAT question.

My skills at CR are good w.r.t all types of questions except the Assumption questions. Recently I have successfully started applying the Least extreme negation/Logical opposites technique to figure out the answers to CR Assumption questions. However, I couldn't get this one correct despite applying those techniques.

I will provide my negations of the relevent answer options below. Can anyone please tell me where did I go wrong while negating the answer options.

Below I have written the original sentence in italics followed by my negated sentence.

(A) There are renewable resource replacements for ALL of the nonrenewable resources currently being consumed.
Negation: There are renewable resource replacements for SOME of the nonrenewable resources currently being consumed


(B) We CANNOT indefinitely replace exhausted nonrenewable resources with other nonrenewable resources.
Negation: We CAN indefinitely replace exhausted nonrenewable resources with other nonrenewable resources

(C) A renewable resource CANNOT be exhausted by human consumption.
Negation: A renewable resource CAN be exhausted by human consumption

(D) Consumption of nonrenewable resources will NOT continue to increase in the future.
Negation:Consumption of nonrenewable resources WILL continue to increase in the future.

(E) Ultimately we cannot do without nonrenewable resources.
Negation: Ultimately, we CAN do without nonrenewable resources.

OA is B. I can't see how that is the correct answer either with or without involving negation....

ChessWriter wrote:Below I have written the original sentence in italics followed by my negated sentence.

(A) There are renewable resource replacements for ALL of the nonrenewable resources currently being consumed.
Negation: There are renewable resource replacements for SOME of the nonrenewable resources currently being consumed


(B) We CANNOT indefinitely replace exhausted nonrenewable resources with other nonrenewable resources.
Negation: We CAN indefinitely replace exhausted nonrenewable resources with other nonrenewable resources

(C) A renewable resource CANNOT be exhausted by human consumption.
Negation: A renewable resource CAN be exhausted by human consumption

(D) Consumption of nonrenewable resources will NOT continue to increase in the future.
Negation:Consumption of nonrenewable resources WILL continue to increase in the future.

(E) Ultimately we cannot do without nonrenewable resources.
Negation: Ultimately, we CAN do without nonrenewable resources.

let me adapt your responses to LSAT patterns.
A) first of all, SOME means "at least one and perhaps all." Obviously you can't negate ALL with SOME. However, let's step away from the answer choice analysis for a moment and think why this question is difficult and the essence of presenting this question in PowerScore's CR Bible?

This question is a classical example of how two equally weighted ideas are expressed in one argument and two consistent conclusions are made. One comes at the end and hopefully gets stuck in our minds by the recency effect described in psychology. The other one is very fragment like but too is expressed as conclusion comes at the beginning of the argument. Both are valid and both are conclusions. Yet the main conclusion must be supported and strengthened for the purposes of our question and we need to find one single assumption among listed five assumptions which voided will make the main conclusion weak, doubtful. The main conclusion comes at the very beginning and to answer the anticipated question as to why the idea expressed in the beginning would be a main conclusion, I would say, because it's more general and culminating the argument.

Sub-conclusion: ultimately we must either do without or turn to renewable resources to take its place.

Note how the word ultimately put at the end of statement masks the argument's main conclusion and shifts out focus to the sub-conclusion. However, the main conclusion is underneath
Main conclusion: The current pattern of human consumption of resources, in which we rely on nonrenewable resources, for example metal ore, must eventually change.

Let's turn to analysis of answer choices as we seem to made it clear the structure of this argument.

choice a) There are renewable resource replacements for all of the nonrenewable resources currently being consumed.

The sub-conclusion says that we either get along with no renewable resources or find the renewable substitute for non-renewable resources. Hence we can still be fine if no substitute of non-renewables exists.

choice b) We cannot indefinitely replace exhausted nonrenewable resources with other nonrenewable resources.

To be honest I could not get the twisted expression "indefinitely replace exhausted ..." and actually negated this one to "We can replace (negation) exhausted nonrenewable resources with other nonrenewable resources up to certain limits, i.e. not all non-renewables can be replaced with other non-renewables and we will lack some types of non-renewables which will be just exhausted - not available.

choice c) A renewable resource cannot be exhausted by human consumption.

This is true but irrelevant to our argument

choice d) Consumption of nonrenewable resources will not continue to increase in the future.

This is falsely claiming something not supported by the argument.

choice e) Ultimately we cannot do without nonrenewable resources.

Repeating the same language used in the argument.

By analyzing all answer choices we get understanding of the choice b) being correct.

ChessWriter wrote:The current pattern of human consumption of resources, in which we rely on nonrenewable resources, for example metal ore, must eventually change. Since there is only so much metal ore available, ultimately we must either do without or turn to renewable resources to take its place.

Which one of the following is an assumption required by the argument?

(A) There are renewable resource replacements for all of the nonrenewable resources currently being consumed.
(B) We cannot indefinitely replace exhausted nonrenewable resources with other nonrenewable resources.
(C) A renewable resource cannot be exhausted by human consumption.
(D) Consumption of nonrenewable resources will not continue to increase in the future.
(E) Ultimately we cannot do without nonrenewable resources.

We must either do without or turn to renewable resources.

The assumption here is that THERE ARE NO OTHER OPTIONS.

The negation of answer choice B shows that there is another option not considered by the passage:
We can indefinitely replace exhausted nonrenewable resources with OTHER NONRENEWABLE RESOURCES.
If the negation of B is true, then the conclusion that we will have to do without or turn to renewable resources is invalidated: instead, we can replace any exhausted nonrenewable resource with ANOTHER NONRENEWABLE RESOURCE.
Since the negation of B invalidates the conclusion, B is the necessary assumption: WHAT MUST BE TRUE for the argument to be valid.

The correct answer is B.