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

Example Input: Problem: sara bought both german chocolate and swiss chocolate for some cakes she was baking . the swiss chocolate cost $ 2.5 per pound , and german chocolate cost $ 1.5 per pound . if the total the she spent on chocolate was $ 30 and both types of chocolate were purchased in whole number of pounds , how many total pounds of chocolate she purchased ? 
Options: a ) 7 , b ) 18 , c ) 10 , d ) 12 , e ) 11
Example Output: b

Example Input: Problem: if two dice are thrown together , the probability of getting prime number on both dice is 
Options: a ) 5 / 9 , b ) 1 / 9 , c ) 2 / 9 , d ) 4 / 9 , e ) 7 / 9
Example Output: c

Example Input: Problem: the ratio of the arithmetic mean of two numbers to one of the numbers is 4 : 7 . what is the ratio of the smaller number to the larger number ? 
Options: a ) 1 : 8 , b ) 1 : 7 , c ) 1 : 6 , d ) 1 : 5 , e ) 1 : 4
Example Output:
b