Let $$A = \begin{bmatrix}0 & 0 & -1 \\0 & -1 & 0 \\-1 & 0 & 0 \end{bmatrix}$$. The only correct statement about the matrix A is

A

$$A$$ is a zero matrix

B

$$A^2 = I$$

C

$$A^{-1}$$ does not exist

D

$$A = (-1)I$$, where I is a unit matrix