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

Ex Input:
Problem: a bottle contains a certain solution . in the bottled solution , the ratio of water to soap is 3 : 5 , and the ratio of soap to salt is four times this ratio . the solution is poured into an open container , and after some time , the ratio of water to soap in the open container is quartered by water evaporation . at that time , what is the ratio of water to salt in the solution ? 
Options: a ) 9 : 100 , b ) 100 : 9 , c ) 12 : 100 , d ) 12 : 20 , e ) 13 : 100

Ex Output:
a


Ex Input:
Problem: the hcf of two numbers is 42 and the other two factors of their lcm are 11 and 12 . what is the largest number . 
Options: a ) 462 , b ) 450 , c ) 480 , d ) 504 , e ) 555

Ex Output:
d


Ex Input:
Problem: 27 is a perfect cube . when x is perfect cube which is added to the prime factor of 27 , the result is not a prime number . what is the square root of x ? 
Options: ['a ) 2', 'b ) 4', 'c ) 6', 'd ) 8', 'e ) 10']

Ex Output:

c