If $0 \leq x < 2 \pi$, then the number of real values of $x$, which satisfy the equation $\cos x + \cos 2x = \cos 3x + \cos 4x = 0,$ is :

Question

$\begin{array}{1 1}(1)3 \\ (2)5 \\ (3) 7 \\ (4) 9 \end{array} $