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: if 45 - [ 28 - { 37 - ( 15 - * ) } ] = 59 , then * is equal to : 
Options: a ) - 29 , b ) - 19 , c ) 20 , d ) 29 , e ) 39

Ex Output:
c


Ex Input:
Problem: if a certain computer is capable of printing 4700 monthly credit card bills per hour , while a new model is capable of printing at a rate of 6800 per hour , the old model will take approximately how much longer than the new model to print 10000 bills ? 
Options: a ) 19 mins , b ) 29 mins , c ) 39 mins , d ) 38 mins , e ) 37 mins

Ex Output:
c


Ex Input:
Problem: if jimmy drinks 8 ounces of water each time for 8 times a day . how much gallons of water he would have to prepare ahead to drink for 5 days ? ( 1 ounce = 0.0078125 gallon ) 
Options: a ) 1 , b ) 1.5 , c ) 2 , d ) 2.5 , e ) 3

Ex Output:

d