Task: Question Answering
Input (English): Problem: the ratio between the presents of the a and b is 6 : 7 . if b is 4 years older than a , what will be the ratio of the ages of a and b after 4 years ? 
Options: a ) 1 : 2 , b ) 9 : 11 , c ) 7 : 8 , d ) 6 : 7 , e ) 3 : 4
Output (English): c