A bond's coupon payment is:______.
a. interest that is paid by the bond issuer when a bond matures a variable interest.
b. amount that is paid to bondholders based on the federal funds rate.
c. a coupon that can be used by bondholders to receive discounts on goods produced by the corporation issuing the bonds.
d. a fixed amount of interest that is paid annually or semiannually by the issuer to its bondholders.