The expected yield on a one-year T-bill at the beginning of year 1 is 7.20%. The expected yield on a one-year T-bill at the beginning of year 2 is 7.80%. Using the pure expectations theory of the term structure of interest rates, what is the expected yield for a U.S. Treasury security note with a two-year maturity?

A. 7.20%

B. 7.50%

C 7.80%

D. 8.00%