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: two passenger trains start at the same hour in the day from two different stations and move towards each other at the rate of 12 kmph and 21 kmph respectively . when they meet , it is found that one train has traveled 60 km more than the other one . the distance between the two stations is ?
Options: a ) 477 , b ) 396 , c ) 279 , d ) 276 , e ) 291
Example Output: b

Example Input: Problem: when the perimeter of a regular polygon is divided by 5 , the length of a side is 25 . what is the name of the polygon ? what is the perimeter ?
Options: ['a ) 125', 'b ) 126', 'c ) 127', 'd ) 128', 'e ) 129']
Example Output: a

Example Input: Problem: 39 persons can repair a road in 12 days , working 5 hours a day . in how many days will 30 persons , working 3 hours a day , complete the work ?
Options: a ) 10 , b ) 26 , c ) 14 , d ) 15 , e ) 16
Example Output:
b