Answer
$\left[\begin{array}{ll}
1 & 0\\
0 & 1
\end{array}\right]$
Work Step by Step
The multiplicative identity matrix $I_{n}$ is an $n\times n$ matrix with 1s down the main diagonal from upper left to lower right and 0s elsewhere.
$I_{2}=\left[\begin{array}{ll}
1 & 0\\
0 & 1
\end{array}\right]$
