Find the most general value of $\theta$ satisfying the equation $\tan\theta=-1$ and $\cos \theta=\large\frac{1}{\sqrt 2}$

Question

$\begin{array}{1 1}(A)\;n\pi+\large\frac{9\pi}{4}&(B)\;2n\pi+\large\frac{7\pi}{4}\\(C)\;3n\pi+\large\frac{7\pi}{4}&(D)\;2n\pi+\large\frac{9\pi}{5}\end{array} $