Task: Question Answering
Input (English): Problem: natasha climbs up a hill , and descends along the same way she went up . it takes her 4 hours to reach the top and 2 hours to come back down . if her average speed along the whole journey is 3.5 kilometers per hour , what was her average speed ( in kilometers per hour ) while climbing to the top ? 
Options: a ) 2.125 , b ) 2.375 , c ) 2.625 , d ) 2.675 , e ) 2.825
Output (English): c