The S.I. on a sum of money for two years is Rs. 660, while C.I. is Rs.696.30, the rate of interest being the same in both the cases. Find the rate of interest.

• A.  \[10%\]         
• B.            \[10\frac{1}{2}%\]      
• C.            \[12%\]         
• D.            \[11%\]