If the sample interest on a sum of money 10% per annum for 2 years is $1200, find the compound interest on the same sum for the same period at the same rate?  Choose the correct option:
A) $ 1260
B) $ 1520
C) $ 1356
D) $ 1440
E) $ 1210

Rationale: rate = 10 % time = 2 years s . i . = $ 1200 principal = 100 * 1200 / 10 * 2 = $ 6000 amount = 6000 ( 1 + 10 / 100 ) ^ 2 = $ 7260 c . i . = 7260 - 6000 = $ 1260 answer is a
Answer: A