IMO B..

My point of reasoning :

Cause : Snacking on Pizza and cookies available....
Effect : Increase in Fat intake...

To weaken this problem we need to show an alternate cause for the same effect. B clearly states that.
Now coming to C. I guess this is not correct because parents are ultimately having an intake of fat and also we dont know what amounts to most of the pizza because most pizza does not mean whole pizza.

My pick is C.
I will discard B on the opinion - Purchasing does not necessarily mean consuming. I can relate it to "Adult Ice-cream consumption " OG question.

In C;however, the fact that children are the primary consumers defeats the point and weakens the most.

I will go with [spoiler]'E'[/spoiler]. Please post OA and please quote the source.

thephoenix wrote:weakening type cr
[spoiler]confused b/n B and C[/spoiler]

Question is - which weakens the explaination of higher fat intakes by parents ( not adults without children)
I would pick C.

B does not give valid justification that higher fat intake takes place due to whole milk and compares it with adults which is not in the scope of the question.
C if true justifies that parents are not likely to increase fat due to the remaining eatables.
D is not relevant.
E compares parents with adults without children which is not in the scope of the question and also not the cause of any explaination to higher fat intakes.

Whats the OA ?

OA IS B

i also went for C

i am still not over on this one