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

Example Input: Problem: the ratio of the present ages of two friends is 2 : 3 and 6 years back , the ratio was 1 : 3 . what will be the ratio of their ages after 4 years ? 
Options: a ) 1 : 4 , b ) 3 : 4 , c ) 1 : 2 , d ) 3 : 1 , e ) 3 : 2
Example Output: b

Example Input: Problem: the ratio of number of boys and girls in a school is 2 : 5 . if there are 490 students in the school , find the number of girls in the school ? 
Options: a ) 150 , b ) 350 , c ) 300 , d ) 370 , e ) 280
Example Output: b

Example Input: Problem: which number is a factor of 20 ? 
Options: a ) 3 , b ) 4 , c ) 7 , d ) 18 , e ) 9
Example Output:
b