Which best describes the zero matrix O=(0000)O = \begin{pmatrix} 0 & 0 \\ 0 & 0 \end{pmatrix}O=(0000)?
A+O=OA + O = OA+O=O for any matrix AAA
A+O=AA + O = AA+O=A for any matrix AAA
OT=AO^T = AOT=A for some matrix A≠OA \neq OA=O
det(O)=1\det(O) = 1det(O)=1