Which of the following personal loans has the highest before-tax cost of debt?
a. borrow $1,000 and pay $1,079 in one year
b. borrow $10,000 and pay $11,236 in two years
c. borrow $5,000 and pay $6,078 in four years
d. borrow $1,000 and pay $156.51 at the end of each year for 10 years.