If the simple interest on a sum of money for 2 years at 5% per annum is Rs. 55, what is the compound interest on the same sum at the rate and for the same time?  Choose the most appropriate option.
A) s . 56.37 B) s . 53.22 C) s . 56.219 D) s . 51.18 E) s . 51.11

Rationale: "explanation : sum = ( 55 * 100 ) / ( 2 * 5 ) = rs . 550 amount = [ 550 * ( 1 + 5 / 100 ) 2 ] = rs . 606.375 c . i . = ( 606.375 - 550 ) = rs . 56.37 answer : a"
Answer: A