GMAT Critical Reasoning (CR) | Re: A recent university survey asked respondents to report the number of h

Solution:

This argument says that X causes Y.
To weaken the argument we need to
1. either provide alternate reason
2. To provide information that X & Y are caused by Z.
3. To reverse the causation.

Option D, uses the Option 3 to weaken the argument.
Therefore, the answer is Option D.

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