In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Input: Consider Input: Problem: working alone , pump a can empty a pool in 6 hours . working alone , pump b can empty the same pool in 9 hours . working together , how many minutes will it take pump a and pump b to empty the pool ? 
Options: a ) 192 , b ) 200 , c ) 208 , d ) 216 , e ) 224

Output: d


Input: Consider Input: Problem: if the wheel is 21 cm then the number of revolutions to cover a distance of 1056 cm is ? 
Options: a ) 8 , b ) 27 , c ) 10 , d ) 7 , e ) 19

Output: a


Input: Consider Input: 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: c