Which one of these bonds is the most interest$-$rate sensitive$?$

Select one or more:

a$.10-$year, $6$ percent, semiannual coupon bond

b$.5-$year zero coupon bond

c$.10-$year, $6$ percent, annual coupon bond

d$.10-$year zero coupon bond

e$.5-$year, $6$ percent, annual coupon bond