1971 AHSME Problem 4

After simple interest for two months at 5% per annum was credited, a Boy Scout Troop had a total of \$255.31 in the Council Treasury. The interest credited was a number of dollars plus the following number of cents

\textbf{(A) }11\qquad \textbf{(B) }12\qquad \textbf{(C) }13\qquad \textbf{(D) }21\qquad \textbf{(E) }31

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.