Since Arlene Hodges was installed as president of the Caralis corporat

When you read an argument like this, the first thing you should do is question the author's logic. Hodges' predecessor saw 7% increase in profit, Hodges is seeing 11%. The reasons for this could be many. The argument states that Hodges' aggressive marketing efforts have caused this increase. But no facts are provided to back this claim. Hence, to weaken this argument, all we need is another reason which led to the increase in profits.

(A) tells you that capacity increased. It doesn't tell you that demand (and hence revenue) increased.
(C) doesn't say what effect the campaign had. Did it rob the company of a lot of money and hence reduced profits. Did it lead to a delayed effect and hence a major increase in revenue, we don't know. We can only speculate and hence this is not a good answer.
(D) doesn't tell us that radio and tv ads are better and capture more audience. Again, the effect is onyl speculation.
(E) tells us that just when Mr. Hodges took over, they had acquired a rival which had doubled the revenues. This gives us a direct impact on the top line by something other than Hodges' marketing activities. Hence, this might be the reason of increased profits. Mind you, we are only given that revenues increased, we d on't know anything about the costs and hence can't say for sure that profits increased. This option only makes us doubt the conclusion, not prove it wrong.
But nevertheless it does weaken it. Hence it is the best among the choices.

Answer (E)