If $$A = \left(\begin{array}{c}0 & -2\\ 2 & 0\end{array}\right)$$ and $$B = \left(\begin{array}{c}1 & 0\\ 0 & -1\end{array}\right)$$, then AB + BA =

A

$$\left(\begin{array}{c}0 & -2\\ 2 & 0\end{array}\right)$$

B

$$\left(\begin{array}{c}1 & 0\\ 0 & -1\end{array}\right)$$

C

$$\left(\begin{array}{c}0 & 0\\ 0 & 0\end{array}\right)$$

D

$$\left(\begin{array}{c}1 & 0\\ 0 & 1\end{array}\right)$$