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