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: the time taken by a man to row his boat upstream is twice the time taken by him to row the same distance downstream . if the speed of the boat in still water is 24 kmph , find the speed of the stream ? 
Options: a ) 18 kmph , b ) 6 kmph , c ) 8 kmph , d ) 10 kmph , e ) 12 kmph
Example Output: c

Example Input: Problem: a man can row upstream at 20 kmph and downstream at 60 kmph , and then find the speed of the man in still water ? 
Options: a ) 32 kmph , b ) 34 kmph , c ) 30 kmph , d ) 45 kmph , e ) 40 kmph
Example Output: e

Example Input: Problem: working individually , julie can peel potatoes in 10 hours and ted can peel potatoes in 8 hours . if julie and ted work together but independently at the task for 4 hours , at which point ted leaves , how many remaining hours will it take julie to complete the task alone ? 
Options: a ) 3 / 15 , b ) 2 / 11 , c ) 1 / 4 , d ) 1 / 3 , e ) 1
Example Output:
e