Figure shows a smooth inclined plane of P inclination \( \theta \) ...

Figure shows a smooth inclined plane of
P inclination \( \theta \) fixed in a car. A sphere is set in pure rolling on the incline. For what value of
W ' \( a \) ' (the acceleration of car in horizontal - direction) the sphere will continue pure rolling?
(1) \( g \cos \theta \)
(2) \( g \sin \theta \)
(3) \( g \cot \theta \)
(4) \( g \tan \theta \)