Let $A$ be a $3 \times 3$ real matrix. Suppose 1 and -1 are two of the three Eigen values of $A$ and 18 is one of the Eigen values of $A^2+3 A$. Then
- Both $A$ and $A^2+3 A$ are invertible
- $A^2+3 A$ is invertible but $A$ is not invertible
- $A$ is invertible but $A^2+3 A$ is not invertible
- Both $\mathrm{A}$ and $A^2+3 A$ are not invertible.