One Intriguing Result from the Studies Comparing Cognitive-Behavioural Therapy (CBT)

One intriguing result from the studies comparing cognitive-behavioural therapy (CBT) and interpersonal therapy (IPT) for bulimia nervosa is the finding that

A) IPT is more effective in the short term but CBT is more effective when we look at how well patients are doing one year following treatment.
B) IPT and CBT appear to be indistinguishable in terms of their effectiveness in the short and long term, despite their very different approaches.
C) IPT is always more effective than CBT.
D) CBT is more effective in the short term, but IPT patients 'catch up' and will do as well as CBT patients one year after treatment.