Keenan Industries has a bond outstanding with 25 years to maturity, a 7.65% nominal coupon, semiannual payments, and a $1,000 par value. The bond has a 6.40% nominal yield to maturity, but it can be called in 6 years at a price of $1,085. What is the bond's nominal yield to call? Do not round your intermediate calculations.

a. 2.88%

b. 4.83%

c. 4.72%

d. 5.97%

e. 5.77%