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: in traveling from a dormitory to a certain city , a student went 1 / 2 of the way by foot , 1 / 4 of the way by bus , and the remaining 6 kilometers by car . what is the distance , in kilometers , from the dormitory to the city ? 
Options: a ) 35 , b ) 24 , c ) 14 , d ) 24 , e ) 12
Example Output: d

Example Input: Problem: a can do a piece of work 60 days . b can do work in 20 days . in how many days they will complete the work together ? 
Options: a ) 12 days , b ) 16 days , c ) 15 days , d ) 17 days , e ) 18 days
Example Output: c

Example Input: Problem: excluding stoppages , the speed of a train is 48 kmph and including stoppages it is 32 kmph . of how many minutes does the train stop per hour ? 
Options: a ) a ) 40 , b ) b ) 30 , c ) c ) 20 , d ) d ) 10 , e ) e ) 5
Example Output:
c