What is the result of R1←12R1R_1 \leftarrow \frac{1}{2}R_1R1←21R1 applied to (4612)\begin{pmatrix} 4 & 6 \\ 1 & 2 \end{pmatrix}(4162)?
(2312)\begin{pmatrix} 2 & 3 \\ 1 & 2 \end{pmatrix}(2132)
(81212)\begin{pmatrix} 8 & 12 \\ 1 & 2 \end{pmatrix}(81122)
(2612)\begin{pmatrix} 2 & 6 \\ 1 & 2 \end{pmatrix}(2162)
(4312)\begin{pmatrix} 4 & 3 \\ 1 & 2 \end{pmatrix}(4132)