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: if 4 spiders make 3 webs in 9 days , then how many days are needed for 1 spider to make 1 web ? 
Options: a ) 9 , b ) 12 , c ) 27 , d ) 24 , e ) 16
Example Output: b

Example Input: Problem: a man can row upstream at 15 kmph and downstream at 25 kmph , and then find the speed of the man in still water ? 
Options: a ) 27 , b ) 29 , c ) 30 , d ) 20 , e ) 24
Example Output: d

Example Input: Problem: if three painters can complete three rooms in two hours , how many hours 5 painters would it take to do 20 rooms ? 
Options: a ) 6 , b ) 9 , c ) 7 , d ) 8 , e ) 5
Example Output:
e