@marquisha (E) is incorrect because it does not accurately describe the role played by the statement about the relative therapeutic success of many popular psychological theories.
This statement is not used to counter the claim that many popular psychological theories do not help to dispel the mystery that surrounds our psyche.
Rather the author is actually claiming that this consideration is "not really important" and goes on to discuss the relative therapeutic success of these theories.
Notice (B) states, "it is used to override some considerations against these theories."
So (B) would be the correct answer.
Hope that helps! Please let us know if you have any other questions.
