This fails to distinguish between belief and fact. People will only expound upon a theory if they believe that it’s true, but they could be mistaken.

No flaw. If there is always some good to be found in even the worst circumstances, then it’s reasonable to conclude that even the most vicious people have brought about some amount of good. (B) doesn’t assume that a belief is factually true, as the stimulus does.

Wrong flaw. This mistakes a necessary condition for a sufficient one. Bringing good to people is a requirement for being a worthy leader, but it doesn’t guarantee that any leader who brings about good is worthy. The stimulus’s flaw is assuming that people’s feelings are facts.

Wrong flaw. This assumes that people’s potential difficulty in distinguishing wishful thinking from reality makes every theory at least partially false. This is a different flaw from that of the stimulus, which assumes that people’s feelings are factually accurate.

Wrong flaw. This draws a universal conclusion from narrow evidence. Just because leaders of scientific revolutions have historically been influenced by false theories doesn’t mean that that influence will always persist. The stimulus, in contrast, is flawed in assuming that people’s feelings are factually accurate.