Task: Question Answering
Input (English): Problem: a boatman trying to cross the river . the width of the river is 400 m . he is selling boat with 10 m / sec . he takes 50 sec to cross the river due to flow of water . calculate the drift . 
Options: a ) 500 , b ) 400 , c ) 300 , d ) 200 , e ) 100
Output (English): c