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: in a theater , the first row has 12 seats and each row has 2 more seats than previous row . if the last row has 48 seats , what is the total number of seats in the theater ? 
Options: a ) 550 , b ) 570 , c ) 590 , d ) 610 , e ) 630

Ex Output:
b


Ex Input:
Problem: in a fuel station the service costs $ 1.75 per car , every liter of fuel costs 0.65 $ . assuming that a company owns 12 cars and that every fuel tank contains 57 liters and they are all empty , how much money total will it cost to fuel all cars ? 
Options: a ) 320.50 $ , b ) 380.50 $ , c ) 425.50 $ , d ) 450.50 $ , e ) 465.60 $

Ex Output:
e


Ex Input:
Problem: a man can swim in still water at 12 km / h , but takes twice as long to swim upstream than downstream . the speed of the stream is ? 
Options: a ) 1.7 , b ) 2.67 , c ) 1.2 , d ) 1.5 , e ) 4

Ex Output:

e