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: pipes a and b can fill a tank in 3 and 4 hours . pipe c can empty it in 4 hours . if all pipes are opened together , then the tank will be filled in ?
Options: a ) 3 hr , b ) 1 / 2 hr , c ) 1 hr , d ) 9 / 7 hr , e ) 5 / 3 hr

Ex Output:
a

Ex Input:
Problem: a trader sells 92 meters of cloth for rs . 9890 at the profit of rs . 24 per metre of cloth . what is the cost price of one metre of cloth ?
Options: a ) 22 , b ) 89.5 , c ) 76.9 , d ) 83.5 , e ) 11

Ex Output:
d

Ex Input:
Problem: a man swims downstream 72 km and upstream 45 km taking 9 hours each time ; what is the speed of the current ?
Options: a ) 3 kmph , b ) 1.5 kmph , c ) 13 kmph , d ) 6.5 kmph , e ) 7 : 3 kmph

Ex Output:
b