APFIVE Continuity of a Piecewise Function
Let $$f(x) = \begin{cases} x^2 - 9 & \text{if } x \neq 3 \\ k & \text{if } x = 3 \end{cases}$$. For what value of $$k$$ is $$f$$ continuous at $$x = 3$$?
A
$$k = -9$$
B
$$k = 9$$
C
No value of $$k$$ makes $$f$$ continuous at $$x = 3$$.
D
$$k = 0$$