Task: Question Answering
Input (English): Problem: speed of a boat in standing water is 9 kmph and the speed of the stream is 6 kmph . a man rows to place at a distance of 210 km and comes back to the starting point . the total time taken by him is : 
Options: a ) 92 hours , b ) 24 hours , c ) 84 hours , d ) 48 hours , e ) none
Output (English): c