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 100 - litre mixture of milk and water contains 36 litres of milk . ' x ' litres of this mixture is removed and replaced with an equal quantum of water . if the process is repeated once , then the concentration of the milk stands reduced at 16 % . what is the value of x ? 
Options: a ) 37.5 litres , b ) 36.67 litres , c ) 37.67 litres , d ) 36.5 litres , e ) 33.33 litres

Ex Output:
e


Ex Input:
Problem: by how much is 12 % of 24.2 more than 10 % of 14.2 ? 
Options: a ) 0.1484 , b ) 14.84 , c ) 1.484 , d ) 2.762 , e ) none

Ex Output:
c


Ex Input:
Problem: sandy bought 65 books for $ 1080 from one shop and 55 books for $ 840 from another shop . what is the average price that sandy paid per book ? 
Options: a ) $ 14 , b ) $ 16 , c ) $ 18 , d ) $ 20 , e ) $ 22

Ex Output:

b