Answer
Q II or Q III
Work Step by Step
From Definition I, we know that-
$\cos\theta$ =$ \frac{x}{r}$
Hence for $\cos\theta$ to be negative, x must be negative as r being a distance cannot be negative.
x is negative in Q II and Q III only, Therefore if $\cos\theta$ is negative, $\theta$ can terminate in Q II or Q III only.
