The 18-year, 9% coupon bonds of Medical Equipment Inc. pay interest semiannually. The bonds have a face value of $1,000 and are currently trading for $1,182.60. What is the companys post-tax cost of debt if its tax rate is 21 percent?

Group of answer choices

7.18 percent

5.67 percent

4.88 percent

3.86 percent

2.40 percent