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: an electric pump can fill a tank in 6 hours . because of a leak in the tank , it took 12 hours to fill the tank . if the tank is full , how much time will the leak take to empty it ? 
Options: a ) 10 hours , b ) 12 hours , c ) 8 hours , d ) 5 hours , e ) 15 hours

Ex Output:
b


Ex Input:
Problem: two trains 140 m and 160 m long run at the speed of 60 km / hr and 40 km / hr respectively in opposite directions on parallel tracks . the time ( in seconds ) which they take to cross each other , is : 
Options: a ) 9 , b ) 9.6 , c ) 10 , d ) 10.8 , e ) 7

Ex Output:
d


Ex Input:
Problem: a car left town a towards town b driving at a speed of v = 32 km / hr . after 3 hours on the road the driver stopped for 15 min in town c . because of a closed road he had to change his route , making the trip 28 km longer . he increased his speed to v = 40 km / hr but still he was 30 min late . find the distance the car has covered . 
Options: a ) 114 , b ) 115 , c ) 116 , d ) 117 , e ) 118

Ex Output:

c