When an insured has a copay at the doctor's office, what form of cost-sharing is it typically considered?

The correct answer identifies copay as a specific type of cost-sharing arrangement. In health insurance, a copay is a fixed amount that an insured person pays for a specific medical service, such as a visit to the doctor. This payment is made at the time of service, and it is distinct from other forms of cost-sharing.

Copayments are designed to share costs between the insurer and the insured, with the insured paying a predetermined amount while the insurance covers the rest. This mechanism helps to control healthcare costs and encourages responsible use of medical services.

In contrast, a deductible is the amount the insured must pay out-of-pocket for healthcare before the insurance begins to cover costs. Coinsurance represents a situation where the insured pays a percentage of the costs after the deductible has been met, rather than a fixed amount. The premium is the regular payment made to maintain the insurance coverage itself and does not directly relate to specific healthcare services.

Thus, copayment specifically describes the nature of the doctor's office visit payment structure, making it the correct answer.