which of the following statements is/are true?

a) all other inputs constant, if a bond's yield to maturity decreases, its price will decrease

b) if a bond's yield to maturity exceeds the coupon rate, the bond will sell at a premium to par

c) a bond that has a coupon rate of 10% will sell at a premium if the required return for bonds of similar risk at 8%

d) more than one are true

e) none of them are true