Let \(A\) and \(B\) be square matrices of order \(n\) satisfying \(AB=O\) where \(O\) is \(n \times n\) zero matrix. Then
Answer & explanation
Correct answer: option 3
$A=\begin{bmatrix}1&0\\0&1\end{bmatrix},B=\begin{bmatrix}0&1\\1&0\end{bmatrix}$
$AB=\begin{bmatrix}1&0\\0&0\end{bmatrix}\begin{bmatrix}0&0\\1&0\end{bmatrix}$
$=\begin{bmatrix}0&0\\0&0\end{bmatrix}$