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

Problem: the ratio between the number of sheep and the number of horses at the stewart farm is 4 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 ) 32 , d ) 56 , e ) 60
c