In this task, you need to provide the correct option for a given problem from the provided options.

Ex Input:
Problem: two vessels p and q contain 62.5 % and 87.5 % of alcohol respectively . if 2 litres from vessel p is mixed with 6 litres from vessel q , the ratio of alcohol and water in the resulting mixture is ? 
Options: a ) 13 : 1 , b ) 13 : 3 , c ) 13 : 8 , d ) 13 : 5 , e ) 13 : 2

Ex Output:
b


Ex Input:
Problem: a certain hobby shop sold model cars for $ 5.00 each and model trains for $ 8.00 each . if a customer purchased both cars and trains from the store for a total of $ 31.00 , what total number of cars and trains did the customer purchase ? 
Options: a ) 3 , b ) 4 , c ) 5 , d ) 6 , e ) 7

Ex Output:
c


Ex Input:
Problem: how many of the positive factors of 19 are not factors of 29 ? 
Options: a ) 0 , b ) 1 , c ) 2 , d ) 3 , e ) 4

Ex Output:

b