The compound interest earned on a sum for the second and the third years are $1200 and $1272 respectively. What is the rate of interest?	Choose the correct option:
A) 4 %  B) 6 %  C) 8 %  D) 10 %  E) 12 %

Rationale: "1272 - 1200 = 72 is the rate of interest on $ 1200 for one year . the rate of interest = ( 100 * 72 ) / ( 1200 ) = 6 % the answer is b ."
Answer: B