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: if one length of a square is tripled , and the original parameter is 4 y . what is the new length of one of the sides ? 
Options: ['a ) 12 y / 3', 'b ) 2 y / 2', 'c ) 6 y / 3', 'd ) 12 y / 4', 'e ) 4 y / 3']
Example Output: d

Example Input: Problem: 42 persons can repair a road in 12 days , working 5 hours a day . in how many days will 30 persons , working 6 hours a day , complete the work ? 
Options: a ) 10 , b ) 16 , c ) 13 , d ) 14 , e ) 19
Example Output: d

Example Input: Problem: bob wants to run a mile in the same time as his sister . if bob ’ s time for a mile is currently 10 minutes 40 seconds and his sister ’ s time is currently 5 minutes 20 seconds , by what percent does bob need to improve his time in order run a mile in the same time as his sister ? 
Options: a ) 3 % , b ) 50 % , c ) 8 % , d ) 10 % , e ) 12 %
Example Output:
b