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'.

Input: Consider Input: Problem: ( 18 ) 7 x ( 5832 ) - 2 ÷ ( 324 ) - 1 = ( 18 ) 7 
Options: a ) 5 , b ) 4 , c ) 3 , d ) 2 , e ) 1

Output: c


Input: Consider Input: Problem: village x has a population of 68000 , which is decreasing at the rate of 1200 per year . village y has a population of 42000 , which is increasing at the rate of 800 per year . in how many years will the population of the two villages be equal ? 
Options: a ) 15 , b ) 19 , c ) 11 , d ) 18 , e ) 13

Output: e


Input: Consider 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


Output: e