Which of these is a scalar matrix?
(2002)\begin{pmatrix} 2 & 0 \\ 0 & 2 \end{pmatrix}(2002)
(1002)\begin{pmatrix} 1 & 0 \\ 0 & 2 \end{pmatrix}(1002)
(2112)\begin{pmatrix} 2 & 1 \\ 1 & 2 \end{pmatrix}(2112)
(0220)\begin{pmatrix} 0 & 2 \\ 2 & 0 \end{pmatrix}(0220)