A student begins to simplify $\sqrt{80}$ and gets the expression $2\sqrt{20}$. Which of the following is true?

The expression is now fully simplified.

The expression is not fully simplified because 20 has a perfect square factor.

The initial step was incorrect; $\sqrt{4}$ is not a factor of $\sqrt{80}$.

The correct simplification is $8\sqrt{10}$.

Which of the following features, if present in a function's graph, would cause the function to be classified as discontinuous?

A point where the graph crosses the x-axis

A single missing point (a hole)