8 In a regular quadrilateral pyramid $S-A B C D$, the angle between the lateral edge and the base is $\alpha$, the angle between the lateral face and the base is $\beta$, the base angle of the isosceles triangle on the lateral face is $\gamma$, and the dihedral angle between two adjacent lateral faces is $\theta$. The size relationship of $\alpha, \beta, \gamma, \theta$ is ( ).
(A) $\alpha<\beta<\gamma<\theta$
(B) $\alpha<\beta<\theta<\gamma$
(C) $\theta<\alpha<\gamma<\beta$
(D) $\alpha<\gamma<\beta<\theta$