If $A(\alpha) = \begin{bmatrix} \cos \alpha & \sin \alpha \\ -\sin \alpha & \cos \alpha \end{bmatrix}$, then $A(\alpha), \; A(\beta)$ is equal to :

Question

( A ) $A(\alpha+ \beta)$
( B ) $A(\alpha)+A(\beta)$
( C ) $A(\alpha)-A(\beta)$
( D ) $A(\alpha-\beta)$