$$A = \begin{bmatrix}2 & 2 & 1 \\ 1 & 2 & 2 \\ 2 & 1 & 2 \end{bmatrix} \Rightarrow (Adj A)^{-1} =$$

A

$$\frac{1}{5}$$ A

B

5A

C

$$\frac{1}{4}$$ A

D

4A