有道陈向东的题目，哪位帮忙解一下好吗

10. A recnet survey showed that 50 percent of people polled believe that elected officials should resign if indicted for a crime, whereas 35 percent believe that elected officials should resign only if they are convicted of a crime. Therefore, more people believe that elected officials should resign if indicted than believe that they should resign if convicted.

The reasoning above is flawed because it

A. darws a conclusion about the population in general based only only on a sample of that population.

B. confuses a sufficient condition with a required condition.

C.is based on an ambiguity of one of its term.

D. draws a conclusion about a specific belief based on responses to queries about two different specific beliefs.

E. contains premises that cannot all be true.

我选了A但是答案是B, 谁是谁的充分和必要，有点不明白。