# A cylindrical vessel filled with water is released on an in inclined plane of angle $\theta$ as shown. The coefficient of friction of surfaces is $(\mu ( < \tan \theta)$. Then the contact angle made by the surface of water with the incline is
$a)\;\tan^{-1}\;\mu \\ b)\;\theta - \tan^{-1}\mu \\ c)\;\theta + \tan^{-1}\mu \\ d)\;\cot^{-1} \mu$