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: train a leaves the station traveling at 30 miles per hour . two hours later train в leaves the same station traveling in the same direction at 36 miles per hour . how many miles from the station was train a overtaken by train b ? 
Options: a ) 320 , b ) 360 , c ) 400 , d ) 440 , e ) 480
Example Output: b

Example Input: Problem: two trains of length 100 meters and 200 meters are 840 meters apart . they are moving towards each other on parallel tracks , at speeds of 54 km / h and 72 km / h . after how many seconds will the trains meet ? 
Options: a ) 20 , b ) 22 , c ) 24 , d ) 26 , e ) 28
Example Output: c

Example Input: Problem: how long will it take a train travelling at 78 kmph to pass an electric pole if the train is 110 meters in lenght ? 
Options: a ) 2.07 , b ) 3.07 , c ) 5.07 , d ) 4.07 , e ) 2
Example Output:
c