The physician submitted a claim on which he had accepted assignment to the third-party payer. The patient signed an assignment-of-benefits statement for the office. The payer determined that the reasonable charge for services provided to the patient was $500 and reimbursed the physician $400. The patient paid $200 at the time services were provided. (The payer required the patient to pay a 20 percent coinsurance amount when services were provided.) The insurance specialist should
a. charge the patient an additional $100.
b. refund the patient a $100 overpayment.
c. return the $400 check to the payer.
d. submit the patient’s name to collections.