Gunther decides Central Perk needs a refresh. He was just thinking of repainting, but Phoebe and Monica convinced him to buy new couches and tiny tables so customers can relax and use the Wi-Fi. Gunthers bank offers to lend Gunther $10,000 for one year at a nominal annual rate of 19.50%, but he must make interest payments at the end of each quarter and then pay off the $10,000 principal amount at the end of the year. What is the effective annual rate on the loan?

a. 19.71%

b. 15.94%

c. 22.02%

d. 20.97%

e. 17.62%