Tango Enterprises has issued 100,000 coupon bonds, with maturity of eight years. Each bond sells for $1,075. The bonds pay semi-annual coupons of 9% on face value of $1,000. What is Tango's cost of debt? Select one: a. 3.86% b. 6.57% c. 7.15% d. 7.28% e. 7.73%