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: excluding stoppages , the speed of a train is 30 kmph and including stoppages it is 21 kmph . of how many minutes does the train stop per hour ? 
Options: a ) 16 , b ) 17 , c ) 12 , d ) 15 , e ) 18
Example Output: e

Example Input: Problem: two consultants can type up a report in 12.5 hours and edit it in 7.5 hours . if mary needs 30 hours to type the report and jim needs 12 hours to edit it alone , how many t hours will it take if jim types the report and mary edits it immediately after he is done ? 
Options: a ) 41.4 , b ) 34.1 , c ) 13.4 , d ) 12.4 , e ) 10.8
Example Output: a

Example Input: Problem: the length of the bridge , which a train 135 m long and traveling at 45 km / hr can cross in 30 sec is ? 
Options: a ) 235 , b ) 240 , c ) 245 , d ) 250 , e ) 255
Example Output:
b