Which of these matrices represents a shear transformation?
(1001)\begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix}(1001)
(1201)\begin{pmatrix} 1 & 2 \\ 0 & 1 \end{pmatrix}(1021)
(01−10)\begin{pmatrix} 0 & 1 \\ -1 & 0 \end{pmatrix}(0−110)
(2002)\begin{pmatrix} 2 & 0 \\ 0 & 2 \end{pmatrix}(2002)