যদি $\mathrm{A}^{2}=\left[\begin{array}{ll}1 & 0 \\0 & 1\end{array}\right]$ হয় তবে $\mathrm{A}=\text { ? }$

$\left[\begin{array}{ll}0 & 0 \\0 & 1\end{array}\right]$

$\left[\begin{array}{ll}1 & 0 \\0 & 0\end{array}\right]$

$\left[\begin{array}{ll}1 & 1 \\1 & 1\end{array}\right]$

$\left[\begin{array}{ll}1 & 0 \\0 & 1\end{array}\right]$