Which of the following matrices are Hermitian?
A = \left [ \begin{matrix} 2 & 3 - i \\ 3 + i & 4 \end{matrix} \right ], B = \left [ \begin{matrix} 1 & 2i \\ -2i & 3 - i \end{matrix} \right ], C = \left [ \begin{matrix} 0 & i & i \\ -i & 0 & i \\ -i & i & 0 \end{matrix} \right ]