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 car runs at the speed of 25 km per hour when not serviced and runs at 75 kmph when serviced . after servicing the car covers a certain distance in 5 hours . how much time will the car take to cover the same distance when not serviced ?
Options: a ) 8 hours , b ) 16 hours , c ) 15 hours , d ) 7 hours , e ) none
Example Output: d

Example Input: Problem: a train 441 m long can cross an electric pole in 21 sec and then find the speed of the train ?
Options: a ) 88 kmph , b ) 89 kmph , c ) 76 kmph , d ) 16 kmph , e ) 18 kmph
Example Output: c

Example Input: Problem: express a speed of 60 kmph in meters per second ?
Options: a ) 10 mps , b ) 16.67 mps , c ) 97.67 mps , d ) 17.67 mps , e ) 18 mps
Example Output:
b