Given the task definition, example input & output, solve the new input case.
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'.
Example: Problem: on a sum of money , the simple interest for 2 years is rs . 330 , while the compound interest is rs . 340 , the rate of interest being the same in both the cases . the rate of interest is 
Options: a ) 15 % , b ) 14.25 % , c ) 6.06 % , d ) 10.5 % , e ) 11.5 %
Output: c
"explanation : the difference between compound interest and simple interest on rs . p for 2 years at r % per annum = ( r ã — si ) / ( 2 ã — 100 ) difference between the compound interest and simple interest = 340 - 330 = 10 ( r ã — si ) / ( 2 ã — 100 ) = 10 ( r ã — 330 ) / ( 2 ã — 100 ) = 10 r = 6.06 % answer : option c"

New input case for you: Problem: solve the quickfire maths brain teaser √ 9 % = ? 
Options: a ) 30 % , b ) 40 % , c ) 85 % , d ) 19 % , e ) 29 %
Output:
a