单选题：Text 2The health-care economy is replete with unusual and ev

Text 2
The health-care economy is replete with unusual and even unique economic relationships.One of the least understood involves the peculiar roles of producer or "provider" and purchaser or"consumer" in the typical doctor-patient relationship, in most sectors of the economy, it is theseller who attempts to attract a potential buyer with various inducements of price, quality, andutility, and it is the buyer who makes the decision. Where circumstances permit the buyer no choice because there is effectively only one seller and the product is relatively essential,government usually asserts monopoly and places the industry under price and other regulations.
Neither of these conditions prevails in most of the health-care irndustry.
In the health-care industry, the doctor-patient relationship is the mirror image of the ordinaryrelationship between producer and consumer. Once an individual has chosen to see a physician and
even then there may be no real choice--it is the physician who usually makes all significantpurchasing decisions: whether the patient should return "next Wednesday", whether X-rays are needed,
whether drugs should be prescribed, etc. It is a rare and sophisticated patient who will challengesuch professional decisions or raise in advance questions about price, especially when the ailmentis regarded as serious.
This is particularly significant in relation to hospital care. The physician must certify the needfor hospitalization, determine what procedures will be performed, and announce when the patientmay be discharged. The patient may be consulted about some of these decisions, but in the main itis the doctor's judgments that are final. Little wonder then that in the systems of the hospital it isthe physician who is the real "consumer". As a consequence, the medical staff represents the"power center" in hospital policy and decision-making, not the administration.
Although usually there are in this situation four identifiable participants--the physician, thehospital, the patient, and the payer (generally an insurance carrier or government )--the physicianmakes the essential decisions for all of them. The hospital becomes an extension of the physician;the payer generally meets most of the real bills generated by the physician/hospital; and for themost part the patient plays a passive role. In routine or minor illnesses, or just plain worries, thepatient's options are, of course, much greater with respect to use and price. In illnesses that are ofsome significance, however, such choices tend to evaporate, and it is for these illnesses that thebulk of the health-care dollar is spent. We estimate that about 75-80 percent of health-careexpenditures" are determined by physicians, not patients. For this reason, economy measuresdirected at patients or the general public are relatively ineffective.
It can be inferred that doctors are able to determine hospital policies because A．it is doctors who generate income for the hospital
B．most of a patient's bills are paid by his health insurance
C．hospital administrators lack the expertise to question medical
D．a doctor is ultimately responsible for a patient's health