Task: Question Answering
Input (English): Problem: a man whose speed is 4.5 kmph in still water rows to a certain upstream point and back to the starting point in a river which flows at 0.5 kmph , find his average speed for the total journey ? 
Options: a ) 4 , b ) 3.5 , c ) 3 , d ) 3.1 , e ) 2.8
Output (English): d