Which of the following bonds is supported by collateral? a) zero coupon bond b) mortgage bond c) debenture bond d) income bond Interest is exempt from federal income taxation on a) equipment trust certificates b) zero coupon bonds c) federal bonds such as savings bonds d) state of Florida bonds Which of the following reduces the investor's risk associated with investing in bonds? 1. a sinking fund 2. a variable interest rate 3. call feature a) 1 and 2 b) 1 and 3 c) 2 and 3 d) 1, 2, and 3