A sum of money has been invested with an interest rate compounded annually to yield Birr 9371.25 at the end of the second year and Birr 9839.8125 at the end of the third year. What was the rate of interest and the sum invested?
A. Birr 9000 at 5%
B. Birr 9000 at 4.5%
C. Birr 8500 at 4.5%
D. Birr 8500 at 5%