In this task, you need to answer the given multiple-choice question on the general math. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

Ex Input:
Problem: a rower whose speed is 2.5 km / hr in still water rows to a certain point upstream and back to the starting point in a river which flows at 0.5 km / hr . what is the rower ' s average speed ( in km / hr ) for the total journey ? 
Options: a ) 2.2 , b ) 2.3 , c ) 2.4 , d ) 2.5 , e ) 2.6

Ex Output:
c


Ex Input:
Problem: in a simultaneous throw of a pair of dice , find the probability of getting a total more than 9 
Options: a ) 1 / 2 , b ) 7 / 18 , c ) 5 / 13 , d ) 5 / 12 , e ) 6 / 17

Ex Output:
b


Ex Input:
Problem: ages of two persons differ by 4 years . if 3 years ago , the elder one was 3 times as old the younger one , find their present age 
Options: a ) 5,9 , b ) 14,18 , c ) 16,20 , d ) 18,22 , e ) 19,23

Ex Output:

a