We are given the following function:

We are asked to determine what type of function is.
An expression of the form:

This means a product of constant and variables elevated to different exponents is called a "monomial". If we have the sum of two monomials, like this:

Then, this is called a binomial.
If we have the sum of three monomials, like for example:

It is called a trinomial. And if we have more than 3 monomials then it is called a "polynomial".
The given function is the quotient between two functions, therefore, it is not any of the given types of functions.
The given function:

Here, we have two monomials:

This means that the expression is a binomial.