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