IMO - D.

Reason - Parallelism visible equipment...unobtrusive equipment.

I eliminated 'E' because 'E' refers to "underestimate it when"..it doesn't fits here

Is it A ?

People tend to overestimate the amount of energy used by x and underestimate that used by y.

That would bring it down to A and D.

D talks about 'visible equipment, such as lights'... The equipment in both the cases are visible.

Do underline the part which is questioned.
It doesn't take much time.

ANS OPT D

sairakesh wrote:Lacking information about energy use, people tend to overestimate the amount of energy used by
equipment. such as lights, that are visible and must be turned on and off and underestimate that used by
unobtrusive equipment, such as water heaters.
(A) equipment, such as lights, that are visible and must be turned on and off and underestimate that
(B) equipment, such as lights, that are visible and must be turned on and off and underestimate it when
(C) equipment, such as lights, that is visible and must be turned on and off and underestimate it when
(D) visible equipment, such as lights, that must be turned on and off and underestimate that
(E) visible equipment, such as lights, that must be turned on and off and underestimate it when

"visible equipment " is concise than "equipment that are/is visible " - Eliminate A,B and C

In E, "underestimate it when" is awkward and also not ||el.

Choose D

good question rakesh

we need parallelism

equipment such as........... obstructive equipment such as........hence visible is required in front of first equipment

left with D and E

D parallel and clear

E though parallel but it when is not required making it unclear.

do D wins

IMO : D

indiantiger wrote:IMO : D

I am sort of confused OG10 says
In B, C, and E, when used by........ nonsensically suggests that the people are used by the equipment.Can anyone explain how will it modify people..


Thanks

First, identify the 2-3 split (it helps and saves time). If we apply the 2-3 split rule here, we can differentiate between A, B and C AND D and E; the former contain the word 'equipment' while the latter 'visible equipment'.

If we go further in the argument we will see that the author makes parallel the unobtrusive equipment and other kind of equipment (in our case the visible one). Therefore, in order to make this sentence parallel discard A, B and C.

The difference between D and E is that E contains additional personal pronoun 'it'. Answer choice E is incorrect because 'it' is not necessary and goes against the rule of parallelism (tend to overestimate and tend to underestimate).

In conclusion, D is the correct choice.

Just to add some points to this post.

Options A, B and C are definitely wrong because they are not parallel with non-underline portion.
Option E is also not parallel as well as incorrectly uses 'when'.