In each of the following pairs of bonds, select the bond that has the highest duration or effective duration: Required a. Bond A is a 6% coupon bond, with a 20 -year time to maturity selling at par value. Bond B is a 6% coupon bond, with a 20 -year time to maturity selling below par value. b. Bond A is a 20 -year noncallable coupon bond with a coupon rate of 6%, selling at par. Bond B is a 20 -year callable bond with a coupon rate of 7%, also selling at par