On a sum of money, the S.I. for 2 years is $600, while the C.I. is $609, the rate of interest being the same in both the cases. The rate of interest is?
Select the correct option:
A) 2 % B) 3 % C) 4 % D) 5 % E) 6 %

Rationale: "difference in c . i . and s . i for 2 years = $ 609 - $ 600 = $ 9 s . i for one year = $ 300 s . i . on $ 300 for 1 year = $ 9 rate = ( 100 * 9 ) / ( 300 ) = 3 % the answer is b ."
Answer: B