Why Is There an Asymmetric Information Problem in the Market

Why is there an asymmetric information problem in the market for health care?

A) The patient, not the physician, knows most about the amount and type of health care to be provided.
B) The government, not the physician, knows most about the amount and type of health care to be provided.
C) Insurance companies, not the physician, know most about the type of health care to be provided.
D) The physician, not the patient, knows most about the amount and type of health care to be provided.