Which of these matrices is a square matrix?
(123456)\begin{pmatrix} 1 & 2 \\ 3 & 4 \\ 5 & 6 \end{pmatrix}135246
(123456)\begin{pmatrix} 1 & 2 & 3 \\ 4 & 5 & 6 \end{pmatrix}(142536)
(1234)\begin{pmatrix} 1 & 2 \\ 3 & 4 \end{pmatrix}(1324)
(123)\begin{pmatrix} 1 & 2 & 3 \end{pmatrix}(123)