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'.

Example Input: Problem: a train 605 m long is running with a speed of 60 km / hr . in what time will it pass a man who is running at 6 km / hr in the direction opposite to that in which the train is going ? 
Options: a ) 81 , b ) 16 , c ) 33 , d ) 54 , e ) 12
Example Output: c

Example Input: Problem: two buses each 3125 m long are running in opposite directions on parallel roads . their speeds are 40 km / hr and 35 km / hr respectively . find the time taken by the slower bus to pass the driver of the faster one ? 
Options: a ) 50 sec , b ) 66 sec , c ) 48 sec , d ) 55 sec , e ) 45 sec
Example Output: a

Example Input: Problem: a car runs at the speed of 55 km per hour when not serviced and runs at 90 kmph when serviced . after servicing the car covers a certain distance in 3 hours . how much time will the car take to cover the same distance when not serviced ? 
Options: a ) 8 hours , b ) 6 hours , c ) 9 hours , d ) 7 hours 12 minutes , e ) none
Example Output:
b