Explain why the function is discontinuous at the given number a$.($Select all that apply.$)$

$f(x)=\{\begin{array}{ccc}\frac{1}{x+4}& if& x-4\\ 1& if& x=-4\\ a=-4\end{array}$

$\underset{x-4}{lim}f(x)$ is not finite.

$\underset{x-4^{+}}{lim}f(x)$ and $\underset{x-4^{-}}{lim}f(x)$ are finite, but are not equal.

$f(-4)$ is defined and $\underset{x-4}{lim}f(x)$ is finite, but they are not equal.

$f(-4)$ is undefined.

none of the above