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 is 410 meter long is running at a speed of 45 km / hour . in what time will it pass a bridge of 140 meter length
Options: a ) 20 seconds , b ) 44 seconds , c ) 40 seconds , d ) 50 seconds , e ) none of these

Ex Output:
b

Ex Input:
Problem: a train running at the speed of 120 km / hr crosses a pole in 18 seconds . what is the length of the train ?
Options: a ) 560 , b ) 570 , c ) 580 , d ) 590 , e ) 600

Ex Output:
e

Ex Input:
Problem: if a car went the first third of the distance at 80 kmh , the second third at 24 kmh , and the last third at 44 kmh , what was the average speed of the car for the entire trip ?
Options: a ) 39 kmh , b ) 40 kmh , c ) 42 kmh , d ) 44 kmh , e ) 50 kmh

Ex Output:
a