Find the Inverse of a If It Has One, or State

Multiple Choice

Find the inverse of A if it has one, or state that the inverse does not exist.
- $$A = \left[ \begin{array} { r r r } 1 & 0 & 0 \\- 1 & 1 & 0 \\1 & 1 & 1\end{array} \right]$$

A) Inverse does not exist
B)
$$\left[ \begin{array} { r r r } 1 & 0 & 0 \\1 & 1 & 0 \\- 2 & - 1 & 1\end{array} \right]$$
C)
$$\left[ \begin{array} { r r r } - 1 & 0 & 0 \\- 1 & - 1 & 0 \\- 1 & - 1 & - 1\end{array} \right]$$
D)
$$\left[ \begin{array} { l l l } 1 & 1 & 1 \\0 & 1 & 1 \\0 & 0 & 1\end{array} \right]$$