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

Example Input: Problem: one lady has 2 children , one of her child is boy , what is the probability of having both are boys 
Options: a ) 1 / 2 , b ) 1 / 3 , c ) 1 / 4 , d ) 1 / 5 , e ) 3 / 4
Example Output: a

Example Input: Problem: how many kilograms of pure water is to be added to 100 kilograms of a 30 % saline solution to make it a 10 % saline solution . 
Options: a ) 100 , b ) 200 , c ) 300 , d ) 400 , e ) 500
Example Output: b

Example Input: Problem: in what ratio mental a at rs . 68 per kg be mixed with another metal at rs . 96 per kg so that cost of alloy ( mixture ) is rs . 72 per kg ? 
Options: a ) 6 : 1 , b ) 4 : 7 , c ) 3 : 7 , d ) 9 : 5 , e ) 9 : 8
Example Output:
a