A homeowner has a $500,000 home with a 30-year mortgage, paid monthly at 4% APR. After five years he receives $60,000 as an inheritance. If he pays this $60,000 toward his mortgage along with his regular payment, by approximately how many years it takes him to pay off his mortgage?

Select one:

a. 16.45

b. 14.36

c. 25.65

d. 19.87