Task: Question Answering
Input (English): Problem: a man can row downstream at 25 kmph and upstream at 15 kmph . find the time to reach a destination point at a distance of 50 km along the downstream . 
Options: a ) 4 hrs . , b ) 1 hrs . , c ) 3 hrs . , d ) 2 hrs . , e ) 2 1 / 2 hrs .
Output (English): d