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'.

Ex Input:
Problem: if 20 typists can type 50 letters in 30 minutes , then how many letters will 40 typists working at the same rate complete in 1 hour ? 
Options: a ) 400 , b ) 500 , c ) 350 , d ) 250 , e ) 200

Ex Output:
a


Ex Input:
Problem: edward earns $ 7.00 per hour for the first 40 hours he works per week , and twice this rate for overtime . if michael earned $ 210 last week , how many hours did he work ? 
Options: a ) 43 , b ) 44 , c ) 45 , d ) 46 , e ) 47

Ex Output:
c


Ex Input:
Problem: how many seconds will a 600 m long train take to cross a man walking with a speed of 3 km / hr in the direction of the moving train if the speed of the train is 63 km / hr ? 
Options: a ) 22 , b ) 36 , c ) 99 , d ) 77 , e ) 12

Ex Output:

b