Which of the following statement is incorrect?

a) The duration of a coupon bond maturing at date T is always less than the duration of a zero-coupon bond maturing on the same date.

b) The modified duration of a bond is always less than the Macaulay duration of the same bond.

c) To measure price sensitivity of a callable bond to the change of interest rates, one needs to calculate the bond's modified duration.

d) Embedded option of a bond reduces its effective duration.