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'.

Ex Input:
Problem: a , b and c can complete a piece of work in 24 , 6 and 12 days respectively . working together , they will complete the same work in :
Options: a ) 33 / 7 , b ) 43 / 7 , c ) 24 / 7 , d ) 19 / 7 , e ) none

Ex Output:
c

Ex Input:
Problem: to fill a tank , 20 buckets of water is required . how many buckets of water will be required to fill the same tank if the capacity of the bucket is reduced to one - fifth of its present ?
Options: a ) 100 , b ) 200 , c ) 300 , d ) 400 , e ) 500

Ex Output:
a

Ex Input:
Problem: a boy wanted to calculate his speed on his bike . his starting point was 350 meters from the turning point . he made the round trip 5 times in 30 minutes . what was the boy ' s speed in kilometers per hour ?
Options: a ) 1.75 , b ) 1 , c ) 2.25 , d ) 2.4 , e ) 3.2

Ex Output:
a