Which of the following describes the column space of the matrix A=(122436)A = \begin{pmatrix} 1 & 2 \\ 2 & 4 \\ 3 & 6 \end{pmatrix}A=123246?
A plane in R3\mathbb{R}^3R3 passing through the origin.
A line in R3\mathbb{R}^3R3 passing through the origin.
The entire space R3\mathbb{R}^3R3.
Only the zero vector.