Which of these matrices is NOT an isometry?
(2001)\begin{pmatrix} 2 & 0 \\ 0 & 1 \end{pmatrix}(2001)
(0110)\begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}(0110)
(−1001)\begin{pmatrix} -1 & 0 \\ 0 & 1 \end{pmatrix}(−1001)
(0−110)\begin{pmatrix} 0 & -1 \\ 1 & 0 \end{pmatrix}(01−10)