3. Proposition 甲: Plane $\alpha \perp$ plane $\beta$, plane $\rho \perp$ plane $\gamma$, then plane $\alpha / /$ plane $\gamma$

Proposition 乙: Three non-collinear points on plane $\alpha$ are equidistant from plane $\beta$, then plane $\alpha / /$ plane $\beta$.
Then ( ).
(A) Proposition 甲 is true, Proposition 乙 is true
(B) Proposition 甲 is true, Proposition 乙 is false
(C) Proposition 甲 is false, Proposition 乙 is true
(D) Proposition 甲 is false, Proposition 乙 is false
3. (D)

For proposition A, construct a cube $A B C D-A_{1} B_{1} C_{1} D_{1}$, with the plane of $A_{1} B_{1} C_{1} D_{1}$ being $\alpha$, and the plane of $B B_{1} D_{1} D$ being $\beta$. It is easy to see that $\alpha \perp \beta$. The plane of $A A_{1} C_{1} C$ is $\gamma$, and it is easy to see that $\beta \perp \gamma$. However, $\alpha / / \gamma$, so proposition A is a false proposition.

For proposition B, construct a cube $A B C D-A_{1} B_{1} C_{1} D_{1}$, with the plane of $A_{1} D_{1} C B$ being $\alpha$, and the plane of $B_{1} C_{1} D A$ being $\beta$. The three non-collinear points $A_{1}, D_{1}, B$ on $\alpha$ are clearly equidistant from $\beta$. However, $\alpha / / \beta$, so proposition B is also a false proposition.