Before His Insurer Will Pay for a Visit to a Dermatologist

Before his insurer will pay for a visit to a dermatologist, it requires Mr. Akers to visit his primary care provider (PCP) and obtain a referral to an in-network dermatologist. Mr. Akers' insurance plan is most likely a(n) :

A) indemnity plan.
B) preferred provider organization
C) Medicare wraparound policy
D) health maintenance organization (HMO) $\degree$