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'.

Input: Consider Input: Problem: some persons can do a piece of work in 12 days . two times the number of these people will do half of that work in ? 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 8

Output: a


Input: Consider Input: Problem: the length of the bridge , which a train 140 metres long and travelling at 45 km / hr can cross in 30 seconds , is ? 
Options: a ) 255 , b ) 267 , c ) 235 , d ) 277 , e ) 211

Output: c


Input: Consider Input: Problem: susan drove an average speed of 15 miles per hour for the first 40 miles of a tripthen at a average speed of 60 miles / hr for the remaining 20 miles of the trip if she made no stops during the trip what was susan ' s avg speed in miles / hr for the entire trip 
Options: a ) 35 , b ) 20 , c ) 45 , d ) 50 , e ) 55


Output: b