Explanation:

The specified yield spread over the reference rate for a floating-rate note (FRN) is referred to as the quoted margin. This margin compensates the investor for the difference in the credit risk of the issuer compared to the risk implied by the reference rate.

• Option A (coupon) is incorrect because the coupon is the actual interest rate paid, which is the reference rate plus the quoted margin, not the spread itself.
• Option C (required margin) is incorrect because the required margin is the yield spread that ensures the FRN is priced at par on a rate reset date, and it fluctuates based on market conditions and the issuer's credit risk, rather than being specified upfront.