Final answer:
A discrete function can have a domain of natural numbers, which are a countable and separate set of numbers. Option A) Natural Numbers is a possible choice for a domain of a discrete function. Examples include the number of classes taken or majors at a university.
Step-by-step explanation:
If a relationship is modeled with a discrete function, the possibility for its domain choices would include options such as natural numbers, integers, or any finite or countably infinite set of numbers. Discrete functions are characterized by having a domain that consists of individual points which are separate from one another, as opposed to continuous functions where the domain includes entire intervals of numbers.
Given the options provided, A) Natural Numbers is a possibility for the domain of a discrete function. Natural numbers, which include 1, 2, 3, and so on, are a classic example of a discrete domain because they are countable and there is a distinct next number in the set. The other options given: rational numbers, irrational numbers, and real numbers can also be part of the domain of a discrete function, but they can equally well represent continuous functions, depending on the context and the definition of the function.
Incorporating examples provided in the practice test solutions, such as the domain of X representing majors at the university or the domain of Y representing the number of classes taken (which can only be whole numbers), these are prime examples of discrete functions. These domains are inherently countable and cannot accept values between the distinctive, separate elements, which aligns with the definition of discrete domains.