Task: Question Answering
Input (English): Problem: the compound ratio of 2 : 3 , 3 : 4 and 4 : 5 ? 
Options: a ) 1 : 2 , b ) 2 : 5 , c ) 3 : 4 , d ) 3 : 5 , e ) 3 : 9
Output (English): b