If A=(1005)A = \begin{pmatrix} 1 & 0 \\ 0 & 5 \end{pmatrix}A=(1005), what is A−1A^{-1}A−1?
(1001/5)\begin{pmatrix} 1 & 0 \\ 0 & 1/5 \end{pmatrix}(1001/5)
(1005)\begin{pmatrix} 1 & 0 \\ 0 & 5 \end{pmatrix}(1005)
(−100−5)\begin{pmatrix} -1 & 0 \\ 0 & -5 \end{pmatrix}(−100−5)
(100−1/5)\begin{pmatrix} 1 & 0 \\ 0 & -1/5 \end{pmatrix}(100−1/5)