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: a garrison of 2000 men has provisions for 54 days . at the end of 15 days , a reinforcement arrives , and it is now found that the provisions will last only for 30 days more . what is the reinforcement ? 
Options: a ) 1800 men , b ) 3900 men , c ) 600 men , d ) 3800 men , e ) 900 men

Ex Output:
c


Ex Input:
Problem: a constructor estimates that 3 people can paint mr khans house in 4 days . if he uses 4 people instead of 3 , how long will they take to complete the job ? 
Options: a ) 2 , b ) 8 , c ) 1 , d ) 3 , e ) 4

Ex Output:
d


Ex Input:
Problem: a and b together can do a work in 8 days . a alone can do it in 12 days . what time b will take to do the work alone ? 
Options: a ) 6 days , b ) 8 days , c ) 12 days , d ) 24 days , e ) 25 days

Ex Output:

d