If $P=\begin{bmatrix}1&1\\2&2\end{bmatrix}, Q=\begin{bmatrix}2&1\\2&2\end{bmatrix}$ and $R=\begin{bmatrix}3&0\\1&3\end{bmatrix}$, which one of the following statements is $TRUE$?

1. $PQ=PR$
2. $QR= RP$
3. $OP=RP$
4. $PO= OR$