What is the result of multiplying the second row of (1246)\begin{pmatrix} 1 & 2 \\ 4 & 6 \end{pmatrix}(1426) by 12\frac{1}{2}21?
(1223)\begin{pmatrix} 1 & 2 \\ 2 & 3 \end{pmatrix}(1223)
(0.5146)\begin{pmatrix} 0.5 & 1 \\ 4 & 6 \end{pmatrix}(0.5416)
(2446)\begin{pmatrix} 2 & 4 \\ 4 & 6 \end{pmatrix}(2446)
(12812)\begin{pmatrix} 1 & 2 \\ 8 & 12 \end{pmatrix}(18212)