Answer
(c). $251^{\circ}$
Work Step by Step
Given-
$\cos\theta$ = - $0.3256$ , $\theta$ belongs to Q III
and $0^{\circ}\leq \theta\lt 360^{\circ}$
We will find reference angle of $\theta$ first, using calculator in degree mode by the $\cos^{-1}$ key with the positive value $0.3256$-
$0.3256$ → $\cos^{-1}$→→ 70.998070238
i.e. reference angle of $\theta$ = $71^{\circ}$ (to the nearest degree)
The desired angle $\theta$ is in Q III, whose reference angle is $71^{\circ}$. Also $0^{\circ}\leq \theta\lt 360^{\circ}$ . Therefore-
$\theta$ = $ 180^{\circ} + 71^{\circ}$
= $251^{\circ}$