GMAT Critical Reasoning (CR) | Re: Doubt.

I think for that you need to keep in mind the basic understanding of Assumption question:
1)In Assumption question the new information from the answer choice is considered correct.
2) Always remember the makers of the GMAT considered their Arguments to be airtight, that is they believe that there is now flaw in their argument.
Especially in case of Cause and effect problems keep the following
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