Interviewer: You have shown that biofeedback, dietary changes, and adoption of proper sleep habits all succeed in cur...

Hi LSAT Max, I chose (C) because I thought "different causes" was pointing at the fact that the therapist's claim seems to shut down any other reason for the treatment not to work. Is this answer choice incorrect because it doesn't really do that, but instead talks about different types of insomnia? Thank you in advance for the help!