a callable bond has 15 years to maturity and can be called in 5 years. the bond's coupon rate is 12% with semi-annual coupon payments. the par value is $1000. if the bond is called, the price will be $1,100. the bond is currently selling for $975.35. what is the difference between its yield-to-call and yield-to-maturity?

a)1.65%

b)1.52%

c)1.03%

d)1.78%

e)0.78%