Final answer:
Option a) (c = 3m) and (c + m = 18) models the situation. Additionally, the total number of ounces of coffee and milk combined is 18, which is represented by the equation c + m = 18.
Step-by-step explanation:
The correct option that models this situation is a) (c = 3m) and (c + m = 18).
This option represents the relationship between the number of ounces of coffee (c) and the number of ounces of milk (m).
In this case, the number of ounces of coffee is 3 times greater than the number of ounces of milk, which is represented by the equation c = 3m.
Additionally, the total number of ounces of coffee and milk combined is 18, which is represented by the equation c + m = 18.