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

Example Input: Problem: in a class of 120 students , 25 did not opt for math . 10 did not opt for science and 2 did not opt for either . how many students of the class opted for both math and science ? 
Options: a ) 63 , b ) 95 , c ) 77 , d ) 87 , e ) 48
Example Output: d

Example Input: Problem: the ratio of the arithmetic mean of two numbers to one of the numbers is 5 : 7 . what is the ratio of the smaller number to the larger number ? 
Options: a ) 2 : 3 , b ) 2 : 5 , c ) 3 : 7 , d ) 4 : 9 , e ) 5 : 6
Example Output: c

Example Input: Problem: ratio of girl and boys in class is 5 : 6 . if 20 girl leave the class and ratio become 2 : 3 . calculate the no . of boys ? 
Options: a ) 100 , b ) 120 , c ) 80 , d ) 90 , e ) none of the above
Example Output:
b