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

Ex Input:
Problem: water consists of hydrogen and oxygen , and the approximate ratio , by mass , of hydrogen to oxygen is 2 : 16 . approximately how many grams of oxygen are there in 162 grams of water ?
Options: a ) 16 , b ) 72 , c ) 112 , d ) 128 , e ) 144

Ex Output:
e

Ex Input:
Problem: the ratio between the number of sheep and the number of horses at the stewart farm is 6 to 7 , if each horse is fed 230 ounces of horse food per day and the farm needs a total 12,880 ounces of horse food per day , what is the number of sheep in the farm ?
Options: a ) 18 , b ) 28 , c ) 48 , d ) 56 , e ) 60

Ex Output:
c

Ex Input:
Problem: how many different positive integers are factors of 20 ?
Options: a ) 6 , b ) 8 , c ) 4 , d ) 10 , e ) 12

Ex Output:
c