If a line in the space makes angles $\alpha, \beta$ and $\gamma$ with the coordinate axes, then $\cos 2 \alpha+ \cos 2 \beta+\cos 2 \gamma +\sin ^2 \alpha +\sin ^2 \beta+\sin ^2 \gamma=$

Question

$$\begin {array} {1 1} (1)\;-1 & \quad (2)\;0 \\ (3)\;1 & \quad (4)\;2 \end {array}$$