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'.

Example Input: Problem: a 21 cm long wire is to be cut into two pieces so that one piece will be 2 / 5 th of the other , how many centimeters will the shorter piece be ?
Options: a ) 12 , b ) 6 , c ) 88 , d ) 77 , e ) 14
Example Output: b

Example Input: Problem: to fill a tank , 25 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 3 / 10 of its present ?
Options: a ) 61.5 , b ) 60.5 , c ) 63.5 , d ) 83.333 , e ) 64.5
Example Output: d

Example Input: Problem: pipe a can fill a tank in 5 hr , pipe b in 10 hr and pipe c in 30 hr . if all the pipes are open in how many hours will tank be filled ?
Options: a ) 1 hr , b ) 2 hr , c ) 3 hr , d ) 4 hr , e ) 5 hr
Example Output:
c