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: the sum of three consecutive even numbers is 63 . find the middle number of the three ? 
Options: a ) 14 , b ) 23 , c ) 25 , d ) 29 , e ) 21
Example Output: e

Example Input: Problem: a train takes 10 sec to pass a signal post and covers a distance of 10 km in 15 min . find the length of train ? 
Options: a ) 100.1 m , b ) 223.1 m , c ) 111.1 m , d ) 120.3 m , e ) 133.4 m
Example Output: c

Example Input: Problem: a train 120 m long running at 60 kmph crosses a platform in 35 sec . what is the length of the platform ? 
Options: a ) 338 , b ) 277 , c ) 463 , d ) 456 , e ) 271
Example Output:
c