Official Explanation
The question asks you to both strengthen and weaken the spokesperson’s conclusion. Treat this problem as a Critical Reasoning Strengthen and Weaken: deconstruct the argument, try to spot the assumptions, and then find a statement that makes the argument a little more likely to be valid (to strengthen) and one that makes it a little less likely to be valid (to weaken).
According to the spokesperson, Maxxus has a particular advantage when a person’s hair is dry: it is better able to restore moisture to hair than are the shampoos of major competitors. The spokesperson then concludes that using Maxxus will help to maximize the health of the customer’s hair.
Is restoring moisture the same thing as maximizing overall health? The spokesperson assumes so, but the argument provides evidence only about restoring moisture. It would strengthen the argument to provide any other information about how Maxxus helps hair health. On the flip side, it would weaken the argument to provide any information about how Maxxus might hurt hair health.
(A) Whether men of a certain age prefer Maxxus does not address hair health, specifically. These men might prefer Maxxus for the cost or the smell or some other attribute that does not have to do with hair health.
(B) Strengthen. If Maxxus shampoo is particularly good for people with oily hair, too, then Maxxus has another “healthy hair” advantage. This strengthens the idea that Maxxus is good for overall hair health, as it works for people with normal moisture levels and is particularly good for people with dry hair or oily hair.
(C) This choice appears to Weaken the argument, but it’s a trap. Even if Maxxus is not as good on dry hair as it is on normal hair, the argument already establishes that Maxxus is one of the best shampoos for dry hair. In other words, it is still better than the major competitors. This choice doesn’t weaken the argument after all.
(D) Weaken. This choice introduces a negative effect for a particular type of hair: Maxxus is more likely to cause dyed hair to break or split. This choice makes it less likely, then, that Maxxus will maximize the overall health of any type of hair, as the spokesperson claims.
(E) Where the product is sold does not address hair health. There are many reasons a salon might sell a particular brand of shampoo, not all of which have to do with hair health.
Column 1: The correct answer is (B).
Column 2: The correct answer is (D).