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

Ex Input:
Problem: the diluted wine contains only 8 liters of wine and the rest is water . a new mixture whose concentration is 30 % , is to be formed by replacing wine . how many liters of mixture shall be replaced with pure wine if there was initially 32 liters of water in the mixture ? 
Options: a ) 2 , b ) 5 , c ) 6 , d ) 7 , e ) 8

Ex Output:
b


Ex Input:
Problem: the present ratio of students to teachers at a certain school is 30 to 1 . if the student enrollment were to increase by 50 students and the number of teachers were to increase by 5 , the ratio of students to teachers would then be 25 to 1 . what is the present number of teachers ? 
Options: a ) 5 , b ) 8 , c ) 10 , d ) 12 , e ) 15

Ex Output:
e


Ex Input:
Problem: a jar contains a mixture of a & b in the ratio 4 : 1 . when 10 l of mixture is replaced with liquid b , ratio becomes 2 : 3 . how many liters of liquid a was present in mixture initially . 
Options: a ) 12 , b ) 15 , c ) 16 , d ) 20 , e ) 25

Ex Output:

c