Definitely B. The wording of the question is deliberately difficult, but it boils down to a special type of Strengthen/Weaken question. It asks for information that would help us evaluate the argument -- that is, for a TYPE of information that would either strengthen or weaken the argument, depending on what exactly that information is. Of course, it is also an EXCEPT question, which means we are actually looking for the one answer which DOESN'T provide this kind of information.
As always, strengthening or weakening the argument is done by building or destroying a connection between evidence and conclusion. In this particular question, the evidence-to-conclusion chain is unusually complicated. It looks like this:
Evidence: Advertisers use images, not rational argument to sell health-oriented or dietary product.
AND: They work on people's insecurities about physical appeal.
AND: They strengthen our obsession with youth.
Therefore, intermediate conclusion: Most consumers choose their health purchases on the basis of unconscious and false expectations.
And therefore, final conclusion: Many Americans today feel disappointed with the reality of their lives and unfulfilled as human beings.
It is fairly easy to see that B is irrelevant to strengthening or weakening this chain of reasoning. How advertisers decide to advertise in a certain way does not matter, because the evidence already tells us what advertisers use to sell these kinds of products. As always in CR, we accept the evidence as true for the purpose of evaluating the argument.
What may be harder is seeing why all the others ARE relevant. A would help determine whether there really is any connection between the activities of advertisers (the three pieces of evidence) and the purported fact that consumers choose these products on the basis of false expectations. C would help determine whether there really is any connection between the advertisers' efforts to foment an obsession with youth (third piece of evidence) and the consumers who are used in the intermediate conclusion. D would indicate whether any of the evidence and the subsidiary conclusion have actually LED to the final conclusion. E would show whether the consumers' way of choosing products (intermediate conclusion) actually is based on the observations in the evidence or not.