Answer
Polynomial function with degree $0$.
Work Step by Step
(a) A function $f(x)$ is said to be a polynomial function when $f(x) = a_nx^n+a_{n-1}x^{n-1}+a_{n-2}x^{n-2}++a_1x+a_0$, where $a_n\ne0$.
(b) A function $f(x)$ is said to be a rational function if $f(x) = \dfrac{a(x)}{b(x)}$ where $a(x)$ and $b(x)$ are known polynomial functions and $b(x) \ne 0$.
The function is not a ratio of polynomials, so it is not rational.
We see that the given function is a polynomial with degree $0$ because the power of $x$ is zero. That is, $3=3x^0$.
