Which of the following pairs of matrices commute under matrix multiplication?
(a) $\left(\begin{array}{rr}1 & 2 \\ -2 & 1\end{array}\right),\left(\begin{array}{ll}2 & 3 \\ 5 & 0\end{array}\right)$,
(b)
$$
\left(\begin{array}{rr}
3 & -1 \\
0 & 2 \\
1 & 4
\end{array}\right),\left(\begin{array}{rrr}
4 & 2 & -2 \\
5 & 2 & 4
\end{array}\right)
$$
(c)
$\left(\begin{array}{rrr}3 & 0 & -1 \\ -2 & -1 & 2 \\ 2 & 0 & 0\end{array}\right),\left(\begin{array}{lll}2 & 0 & -1 \\ 1 & 1 & -1 \\ 2 & 0 & -1\end{array}\right)$