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

Ex Input:
Problem: how many of the positive factors of 42 are not factors of 56 ? 
Options: a ) 1 , b ) 2 , c ) 3 , d ) 4 , e ) 5

Ex Output:
c


Ex Input:
Problem: bag a contains red , white and blue marbles such that the red to white marble ratio is 1 : 3 and the white to blue marble ratio is 2 : 3 . bag b contains red and white marbles in the ratio of 1 : 4 . together , the two bags contain 26 white marbles . how many red marbles could be in bag a ? 
Options: a ) 1 , b ) 3 , c ) 4 , d ) 2 , e ) 8

Ex Output:
d


Ex Input:
Problem: the ratio of pens to pencils is 5 to 6 . there are 7 more pencils than pens . how many pencils are there ? 
Options: a ) 36 , b ) 42 , c ) 48 , d ) 55 , e ) 64

Ex Output:

b