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: car a is 30 miles behind car b , which is traveling in the same direction along the same route as car a . car a is traveling at a constant speed of 58 miles per hour and car bis traveling at a constant speed of 50 miles per hour . how many hours will it take for car a to overtake and drive 8 miles ahead of car b ? 
Options: a ) 1.5 , b ) 4.5 , c ) 4.75 , d ) 3.75 , e ) 3.5
Example Output: c

Example Input: Problem: express a speed of 46 kmph in meters per second ? 
Options: a ) 10.78 mps , b ) 12.78 mps , c ) 97.78 mps , d ) 17.78 mps , e ) 18.78 mps
Example Output: b

Example Input: Problem: pipe a can fill a tank in 10 hours . due to a leak at the bottom , it takes 15 hours for the pipe a to fill the tank . in what time can the leak alone empty the full tank ? 
Options: a ) 76 , b ) 84 , c ) 56 , d ) 75 , e ) 30
Example Output:
e