Definition: In this task, you need to answer the given multiple-choice question on the gain. Gain is the value by which to multiply the input. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.
Input: Problem: on a sum of money , the s . i . for 2 years is $ 660 , while the c . i . is $ 693 , the rate of interest being the same in both the cases . the rate of interest is ? 
Options: a ) 10 % , b ) 32 % , c ) 72 % , d ) 14 % , e ) 82 %
Output:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
a