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 running at a speed of 60 kmph crosses a pole in 18 seconds . what is the length of the train ?
Options: a ) 120 m , b ) 300 m , c ) 190 m , d ) 150 m , e ) 160 m

Ex Output:
b

Ex Input:
Problem: a crow leaves its nest , and flies back and forth from its nest to a nearby ditch to gather worms . the distance between the nest and the ditch is 100 meters . in one and a half hours , the crow manages to bring worms to its nest 15 times . what is the speed of the crow in kilometers per hour ?
Options: a ) 1 , b ) 2 , c ) 3 , d ) 5 , e ) 7

Ex Output:
d

Ex Input:
Problem: timothy leaves home for school , riding his bicycle at a rate of 6 miles per hour . fifteen minutes after he leaves , his mother sees timothy ' s math homework lying on his bed and immediately leaves home to bring it to him . if his mother drives at 36 miles per hour , how far ( in terms of miles ) must she drive before she reaches timothy ? i think is a 700 level problem but i tag it as 600 / 700 , let me know . either way i hope in an explanationthanks
Options: a ) 1 / 3 , b ) 9 / 5 , c ) 4 , d ) 9 , e ) 12

Ex Output:
b