O'Brien Ltd.'s outstanding bonds have a $1,000 par value, and they mature in 15 years. Their nominal annual, not semiannual yield to maturity is 7.50%, they pay interest semiannually, and they sell at a price of $850. What is the bond's nominal coupon interest rate? Do not round your intermediate calculations.

a. 5.61% b. 2.91% c. 2.80% d. 5.82% e. 5.40%