请问 boldface中第二题 b选项的anti-consideration是什么意思

请问nn, boldface中第二题 b选项的anti-consideration是什么意思啊？

2. A double-blind study, in which neither the patient nor the primary researcher knows whether the patient is being given the drug being tested or a placebo, is the most effective procedure for testing the efficacy of a drug. But we will not be able to perform such a study on this new drug, since the drug will have various effects on the patients’ bodies, which will make us aware of whether the patients are getting the drug or a placebo.

The two portions in boldface play which of the following roles?

(A) The first is a general consideration that introduces the argument; the second is a special situation that weighs against the first.

(B) The first is a general principle that is necessary for this argument; the second is an anti-consideration that the argument includes.

(C) The first is a premise that this argument includes; the second is a main idea that can be drawn from this argument.

(D) The first is an evidence that this argument includes; the second is a conclusion that can not be drawn from this argument.

(E) The first is a general situation that supports this argument; the second is a conclusion that can be drawn from a special fact.

应该和anticlimax 相同的解读。表示反的，反向的， 意思大概是反考虑， 考虑不适合的情况， 不知对否。

选什么c? b吧