After Controlling for Researcher Allegiance Effects,meta-Analysis of Humanistic Therapy's Effectiveness

After controlling for researcher allegiance effects,meta-analysis of humanistic therapy's effectiveness concluded that humanistic therapies are generally:

A) about as effective as other major approaches to therapy.
B) less effective than other major approaches to therapy.
C) more effective than other major approaches to therapy.
D) less influenced by allegiance effects than other therapies.