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 14 men do a work in 80 days , in how many days will 20 men do it ? 
Options: a ) 18 days , b ) 38 days , c ) 42 days , d ) 48 days , e ) 56 days
Example Output: e

Example Input: Problem: if a tire rotates at 400 revolutions per minute when the car is traveling 72 km / h , what is the circumference of the tire ? 
Options: a ) 7 meters , b ) 9 meters , c ) 8 meters , d ) 5 meters , e ) 3 meters
Example Output: e

Example Input: Problem: a train 420 m long is running at a speed of 48 km / hr . in what time will it pass a bridge 60 m long ? 
Options: a ) 40 sec , b ) 36 sec , c ) 60 sec , d ) 48 sec , e ) 18 sec
Example Output:
b