Which of the Following Is an Example of an HMO

Which of the following is an example of an HMO?

A) Nurse practitioners are paid promptly at discounted fees for each service rendered at a women's health clinic.
B) Physicians in a large urban center are reimbursed for visits made to their clients.
C) Physicians are paid for each service delivered to enrolled patients through a prepaid plan.
D) Patients pay fixed annual fees for ambulatory care services, regardless of actual utilization of health services.