Which of the following is true for the matrix A=(1000)A = \begin{pmatrix} 1 & 0 \\ 0 & 0 \end{pmatrix}A=(1000)?
The column space is the entire R2\mathbb{R}^2R2
The rank is 2
The null space is spanned by (01)\begin{pmatrix} 0 \\ 1 \end{pmatrix}(01)
The matrix is invertible