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

Question $9$Select one:

a$.$

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

b$.$

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

c$.$

$5-$year zero coupon bond

d$.$

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