The matrix $A =\begin{bmatrix}0&1&-3\\-1&0&0\\3&0&0\end{bmatrix}$ is a

Diagonal matrix Symmetric matrix Skew-symmetric matrix Scalar matrix

Skew-symmetric matrix

$A =\begin{bmatrix}0&1&-3\\-1&0&0\\3&0&0\end{bmatrix}$ $A^T =\begin{bmatrix}0&-1&3\\1&0&0\\-3&0&0\end{bmatrix}$ $A=-A^T$ ⇒ A is Skew-symmetric matrix