If \[A = \left[ {\begin{array}{*{20}{c}}
  a&b
\end{array}} \right],\,B = \left[ {\begin{array}{*{20}{c}}
  { - b}&{ - a}
\end{array}} \right]\,\] and \[C = \left[ {\begin{array}{*{20}{c}}
  a \\
  { - a}
\end{array}} \right]\] then the correct statement is