Instead of Referring to a Sample of Comments a Doctor

Instead of referring to a sample of comments a doctor has provided on her own website, I have decided instead to rely on reviews from friends who have been her patients. What type of asymmetric information problem am I trying to correct by soliciting comments from friends?

A) diminishing returns
B) adverse selection
C) moral hazard
D) principal-agent problem
E) an adverse selection problem that became a principal-agent problem