Ram Enterprises' bonds currently sell for $968. They have a 10-year maturity, a coupon rate of 6% paid on semi-annual basis. Its par value is $1,000 and it is callable in three years with a call price of $1,020. What is their yield-to-call?
a.7.82%
b.7.50%
c.6.69%
d.6.27%
e.5.68%