大全-A-15.   Alba: I don’t intend to vote for Senator Frank in the next election. She is not a strong supporter of the war against crime.

Tam: But Senator Frank sponsored the latest anticrime law passed by the Senate.

Alba: If Senator Frank sponsored it, it can’t be a very strong anticrime law.

Which of the following identifies the most serious logical flaw in Alba’s reasoning?

(A) The facts she presents do not support her conclusion that Senator Frank is soft on crime.

(B) She assumes without proof that crime is the most important issue in the upcoming election.

(C) She argues in a circle, using an unsupported assertion to dismiss conflicting evidence.

(D) She attacks Senator Frank on personal grounds rather than on he merit as a political leader.（C）

(E) In deciding not to vote for Senator Frank, she fails to consider issues other than crime.

应该就是循环论证，用自己的一个尚未证明的假设，来作论据。也就是说，他的第二句话是基于他第一句话正确的基础上的，而第一句话也仅仅是他的一个assersion。

argue in circle:用循环论证法来辩论(先假设结论是前提的证据, 又利用前提去证明结论)

D是错的，Alba并没有对senator私人方面的事情进行攻击啊。

C很明显啊。其实应该看后半段，前半段in a circle是很模糊的概念，不要去看查字面上的意思。using an unsupported assertion to dismiss conflicting evidence。 从原文中可以找到match。