Tables for finctions $f$ and $g$ are given. Evaluate cach expression, if possible.
(a) $(g \circ f)(1)$(b) $(f \circ g)(4)$(c) $(f \circ f)(3)$
$$\begin{array}{c|c}x & f(x) \\1 & 4 \\2 & 3 \\3 & 1 \\4 & 2\end{array}\quad\quad\quad
\begin{array}{c|c}x & g(x) \\1 & 2 \\2 & 3 \\3 & 4 \\4 & 5\end{array}$$