Ryugais Discussing Cognitive-Behavioural Therapies with His Psychology Professor

Ryugais discussing cognitive-behavioural therapies with his psychology professor.His psychology professor points out that although it doesn't work for everyone,cognitive-behavioural therapy has been proven effective for treating many psychological problems.Ryugais points out one more limitation,impressing his professor.Which of the following was the limitation of cognitive-behavioural therapies that Ryugais pointed out?

A) It isn't always clear that maladaptive thoughts are at the centre of the problem.
B) They ignore unconscious thoughts as an influence on behaviour.
C) They focus on what is wrong with the individual instead of focusing on positive qualities.
D) They are very costly and take a long time.