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 copy machine , working at a constant rate , makes 40 copies per minute . a second copy machine , working at a constant rate , makes 55 copies per minute . working together at their respective rates , how many copies do the two machines make in half an hour ? 
Options: a ) 90 , b ) 2,700 , c ) 4,500 , d ) 5,400 , e ) 2,850
Example Output: e

Example Input: Problem: to fill a tank , 20 buckets of water is required . how many buckets of water will be required to fill the same tank if the capacity of the bucket is reduced to one - fifth of its present ? 
Options: a ) 100 , b ) 200 , c ) 300 , d ) 400 , e ) 500
Example Output: a

Example Input: Problem: jerry travels 8 miles at an average speed of 40 miles per hour , stops for 15 minutes , and then travels another 20 miles at an average speed of 60 miles per hour . what is jerry ’ s average speed , in miles per hour , for this trip ? 
Options: a ) 35 , b ) 42.5 , c ) 44 , d ) 50 , e ) 52.5
Example Output:
a