Which of the following is a function whose graph is continuous everywhere except at $3$ and is continuous from the left at $3$?

(a) $f(x)=x$.
(b) $f(x) = \begin{cases} 4-x^2 & \textrm{if }x \leq 3 \\ x-8 & \textrm{if }x>3 \\ \end{cases}$.
(c) $f(x) = \begin{cases} 2-x^2 & \textrm{if }x \leq 3 \\ 3-x & \textrm{if }x > 3 \\ \end{cases}$.