Task: Question Answering
Input (English): Problem: liz drove from point a to point b at 40 km / h . on her way back she drove at 50 km / h and therefore her way back lasted one hour less . what is the distance ( in km ) between a and b ? 
Options: a ) 150 , b ) 200 , c ) 450 , d ) 500 , e ) 600
Output (English): b