In this task, you need to provide the correct option for a given problem from the provided options.

Example Input: Problem: the least whole number which when subtracted from both the terms of the ratio 6 : 7 to give a ratio less than 16 : 21 , is ? 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 7
Example Output: a

Example Input: Problem: two whole numbers whose sum is 36 can not be in the ratio 
Options: a ) 2 : 4 , b ) 3 : 4 , c ) 3 : 6 , d ) 1 : 3 , e ) 3 : 36
Example Output: b

Example Input: Problem: what is the square root of 225 ? 
Options: a ) 6 , b ) 9 , c ) 12 , d ) 45 , e ) 15
Example Output:
e