What Conclusion Does Stevens Et Al

What conclusion does Stevens et al. (2000) draw about common versus specific factors in therapy?

A) Specific factors are more important for severe disorders than common factors
B) Common factors are more important for severe disorders than specific factors
C) Common and specific factors have an equal role to play in all forms of disorder
D) Specific factors are more important than common factors regardless of severity of disorder
E) Common factors are more important than specific factors regardless of severity of disorder