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 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: if teena is driving at 55 miles per hour and is currently 7.5 miles behind joe , who is driving at 40 miles per hour in the same direction then in how many minutes will teena be 22.5 miles ahead of joe ? 
Options: a ) 15 , b ) 60 , c ) 75 , d ) 90 , e ) 120
Example Output: e

Example Input: Problem: the h . c . f . of two numbers is 12 and their l . c . m . is 600 . if one of the numbers is 720 , then the other is : 
Options: a ) 8 , b ) 10 , c ) 12 , d ) 4 , e ) 6
Example Output:
c