A 25-year maturity, 7.4% coupon bond paying coupons semiannually is callable in six years at a call price of $1,180. The bond currently sells at a yield to maturity of 6.4% (3.20% per half-year).

a. What is the yield to call?

b. What is the yield to call if the call price is only $1,130?

c. What is the yield to call if the call price is $1,180 but the bond can be called in three years instead of six years?