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

Input: Consider Input: Problem: a can contains a mixture of liquids a and b is the ratio 7 : 5 . when 9 litres of mixture are drawn off and the can is filled with b , the ratio of a and b becomes 7 : 9 . how many liter e of liquid a was contained by the can initially ? 
Options: a ) 10 , b ) 20 , c ) 21 , d ) 25 , e ) 27

Output: c


Input: Consider Input: Problem: a container holding 12 ounces of a solution that is 1 part alcohol to 2 parts water is added to a container holding 12 ounces of a solution that is 1 part alcohol to 3 parts water . what is the ratio of alcohol to water in the resulting solution ? 
Options: a ) 2 : 5 , b ) 3 : 7 , c ) 3 : 5 , d ) 4 : 7 , e ) 7 : 17

Output: e


Input: Consider Input: Problem: the l . c . m of two numbers is 48 . the numbers are in the ratio 4 : 3 . the sum of numbers is : 
Options: a ) 28 , b ) 30 , c ) 40 , d ) 50 , e ) 60


Output: a