Critical Reasoning

How to read the relation? any example?

Y has been believed to cause Z. A new report, noting that Y and Z are often observed to be preceded by X, suggests that X, not Y, may be the cause of Z.

Which of the following further observations would best support the new report's suggestion?

In cases where X occurs but Y does not, X is usually followed by Z.
In cases where X occurs, followed by Y, Y is usually followed by Z.
In cases where Y occurs but X does not, Y is usually followed by Z.
In cases where Y occurs but Z does not, Y is usually preceded by X.
In cases where Z occurs, it is usually preceded by X and Y.

Answer : A

This is a cause and effect question .

Cause --------> Effect

X causes ---------> Z .

Now we need to support the new report that makes the claim and any premise that eliminates the others factors that causes Z and proves that Z is caused only when X occurs is the correct answer .

choice (A) dose exactly that it shows that when X occurs Z too occurs and Y dose not . So we can definitely say X causes Z.

Where as in option (E) which is a very close contender also says that Z is preceded by X and Y so we can not definitely say

If Z is caused by X or Y or both X and Y .

Same problem is repeated in choice (B)


Option C shows Y causes Z and in fact weakens the argument.

Same for D weakens .

Correct is (A)

IMO A