You Purchase a 30-Year, Zero-Coupon Bond for a Price of $20

You purchase a 30-year, zero-coupon bond for a price of $20. The bond will pay back $100 after 30 years and make no interim payments. The annual compounded return (geometric average return) on this investment is

A) 4.78%.
B) 5.31%.
C) 6.54%.
D) 5.51%.