Which of the following best describes a rational function?

A rational function is defined as a function that can be expressed as the quotient of two polynomials. This means that a rational function takes the form of one polynomial divided by another polynomial. For example, a function like ( f(x) = \frac{p(x)}{q(x)} ), where ( p(x) ) and ( q(x) ) are both polynomial functions, is considered a rational function.

This definition captures the essential characteristic of rational functions, including their potential for asymptotic behavior and discontinuities, which arise from the division by a polynomial that could be zero for certain input values. The concept of being able to represent the function as a ratio of polynomials is key in understanding their properties, graphing them, and analyzing their behavior in various contexts.

The other options describe different types of functions that do not encapsulate the specific definition of a rational function as succinctly and accurately as the correct choice does.