Solve this
Q.130. A block of mass m is placed on a smooth inclined wedge ABC of inclination $\theta$ as shown in the figure. The wedge is given an acceleration 'a' towards the right. The relation between a and $\theta$ for the block to remain stationary on the wedge is

(1) $a=\frac{g}{\sin \theta }$
(2) a = g cos $\theta$
(3) $a=\frac{g}{\cos ec\theta }$
(4) a = g tan $\theta$