Which of the following statements is NOT CORRECT? a) a zero coupon bond is a bond that pays no annual interest and is sold at a discount below par when initially offered for sale. b) Since floating-rate debt shifts price risk to companies, it offer no advantages to corporate issuers. c) Other things equal, a firm will have to pay a higher coupon rate on its subordinated debentures than on its second mortgage bonds. d) There is an inverse relationship between bonds' quality ratings and their required rates of return.