one question for help

The argument that the author is making is:

because drug addicts manipulate others much more than non addicts then it stands to reason that manipulative people are going to become addicts.

The question wants you to weaken this conclusion. The easiest way to do that is to find a way to flip it around. His theory is that manipulative people are likely to become addicts. The reverse way to look at it is that being a drug user leads a person to be manipulative and that they were not manipulative before drugs.

A. Correct. This is exactly what we want in an answer. It tells us that the addicts learn after becoming addicted to manipulate. If they learn after they are addicts then we cant say that manipulative people become addicts. Instead we say that addicts become manipulative.

B. Incorrect. We are looking for correlation between drug addiction and manipulative skills. How they use their ability is unimportant.

C. Incorrect. The author already stated "on average" so he agrees some non-addicts are more manipulative.

D. Incorrect. Just because they have other behaviors does not mean that the manipulation trait does not make them become addicts. The authors argument is manipulators become addicts. Imagine if you have a group of 100 people. 80 people show some type of strange behavior and 20 are manipulators. Of that group 79 of the other behaviors become addicts and 19 manipulators become addicts. So the other behaviors are more likely, but at the same time the manipulators are also very likely to become addicts. That could possibly strengthen the position.

E. Incorrect. How good or bad they were is not the issue here.