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: 45 men working 8 hours per day dig 40 m deep . how many extra men should be put to dig to a depth of 50 m working 6 hours per day ? 
Options: a ) 10 , b ) 20 , c ) 30 , d ) 40 , e ) 50

Ex Output:
c


Ex Input:
Problem: a train 140 m long is running with a speed of 50 km / hr . in what time will it pass a man who is running at 4 km / hr in the direction opposite to that in which the train is going ? 
Options: a ) 8.1 , b ) 7.0 , c ) 9.33 , d ) 8 , e ) 9

Ex Output:
c


Ex Input:
Problem: a man ' s regular pay is $ 3 per hour up to 40 hours . overtime is twice the payment for regular time . if he was paid $ 174 , how many hours overtime did he work ? 
Options: a ) 8 , b ) 5 , c ) 9 , d ) 6 , e ) 10

Ex Output:

c