gwd16的一道逻辑题,大家帮我看看啊

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3. GWD25-Q3.

Mel: The official salary for judges has always been too low to attract the best candidates to the job. The legislature’s move to raise the salary has done nothing to improve the situation, because it was coupled with a ban on receiving money for lectures and teaching engagements.

Pat:  No, the raise in salary really does improve the situation. Since very few judges teach or give lectures, the ban will have little or no negative effect.

Pat’s response to Mel is inadequate in that it

A.      attempts to assess how a certain change will affect potential members
        of a group by providing evidence about its effect on the current members.

B.       mistakenly takes the cause of a certain change to be an effect of that change

C.      attempts to argue that a certain change will have a positive effect merely by pointing to the absence of negative effects

D.      simply denies Mel’s claim without putting forward any evidence in support
        of that denial

E.       assumes that changes that benefit the most able members of a group
        necessarily benefit all members of that group.

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答案是A为什么不选C啊？？