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'.

Ex Input:
Problem: a train 1500 m long can cross an electric pole in 50 sec and then find the speed of the train ? 
Options: a ) 106 , b ) 107 , c ) 108 , d ) 109 , e ) 110

Ex Output:
c


Ex Input:
Problem: a and b together can do a piece of work in 6 days and a alone can do it in 13 days . in how many days can b alone can do it ? 
Options: a ) 12 days , b ) 15 days , c ) 78 / 7 days , d ) 21 days , e ) 22 / 7 days

Ex Output:
c


Ex Input:
Problem: the end of a blade on an airplane propeller is 5 feet from the center . if the propeller spins at the rate of 1,320 revolutions per second , how many miles will the tip of the blade travel in one minute ? ( 1 mile = 5,280 feet ) 
Options: a ) 200 π , b ) 240 π , c ) 300 π , d ) 480 π , e ) 150 π

Ex Output:

e