The set of all solutions of the equation $\cos 2 \theta = \sin \theta + \cos \theta$ is given by\\
(a) $\theta = 0$.\\
(b) $\theta = n \pi + \frac { \pi } { 2 }$, where $n$ is any integer.\\
(c) $\theta = 2 n \pi$ or $\theta = 2 n \pi - \frac { \pi } { 2 }$ or $\theta = n \pi - \frac { \pi } { 4 }$, where $n$ is any integer.\\
(d) $\theta = 2 n \pi$ or $\theta = n \pi + \frac { \pi } { 4 }$, where $n$ is any integer.