Find the Inverse of the Invertible Matrix $\left[ \begin{array} { l l l } 1 & 0 & 0 \\ 1 & 1 & 0 \\ 1 & 1 & 1 \end{array} \right]$

Multiple Choice

Find the inverse of the invertible matrix.
- $\left[ \begin{array} { l l l } 1 & 0 & 0 \\ 1 & 1 & 0 \\ 1 & 1 & 1 \end{array} \right]$

A) $\left[ \begin{array} { c c c } 1 & 0 & 0 \\ 1 & 1 & 1 \\ 0 & - 1 & 1 \end{array} \right]$
B) $\left[ \begin{array} { r r r } 1 & 0 & 0 \\ - 1 & - 1 & 0 \\ 0 & 1 & 1 \end{array} \right]$
C) $\left[ \begin{array} { r r r } 1 & 0 & - 1 \\ - 1 & 1 & 0 \\ 0 & - 1 & 1 \end{array} \right]$
D) $\left[ \begin{array} { r r r } 1 & 0 & 0 \\ - 1 & 1 & 0 \\ 0 & - 1 & 1 \end{array} \right]$