考虑以下两个语句。
S1: If a candidate is known to be corrupt, then he will not be elected.
S2: If a candidate is kind, he will be elected.根据逻辑的声音推理规则，从S1和S2遵循以下哪个陈述?
(A)如果已知某人是腐败的，那么他是善良的
(B)如果不知道某人有腐败行为，那么他就不会友善
(C)如果一个人是善良的，就不知道他是腐败的
(D)如果一个人不友善，就不知道他是腐败的答案： (C)
解释：
S1: If a candidate is known to be corrupt, then
he will not be elected.
S2: If a candidate is kind, he will be elected.
If p → q, then ¬q → ¬p
So from S1, elected → not corrupt
and S2 is, kind → elected
Therefore, kind → not corrupt
这个问题的测验