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: two trains of equal length , running with the speeds of 60 and 90 kmph , take 50 seconds to cross each other while they are running in the same direction . what time will they take to cross each other if they are running in opposite directions ? 
Options: a ) 3.2 , b ) 2.6 , c ) 6.6 , d ) 32.2 , e ) 42.2
Example Output: c

Example Input: Problem: excluding stoppages , the speed of a bus is 86 kmph and including stoppages , it is 76 kmph . for how many minutes does the bus stop per hour ? 
Options: a ) 7.5 min , b ) 16 min , c ) 20 min , d ) 7 min , e ) 40 min
Example Output:
d