Task: Question Answering
Input (English): Problem: a rower can row 7 km / h in still water . when the river is running at 2 km / h , it takes the rower 1 hour to row to big rock and back . how many kilometers is it to big rock ? 
Options: a ) 2.92 , b ) 3.04 , c ) 3.12 , d ) 3.21 , e ) 3.35
Output (English): d