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 as acceleration 'a' towards the right. The relation between a and $\theta$ for the block to remain stationary on the wedge is <br>

Question

( A ) $a = \frac{a}{\sin\; \theta}$
( B ) $a =g \tan \theta$
( C ) $a = \frac{a}{\mathrm{cosec}\; \theta}$
( D ) $a = g\; \mathrm{cosec}\; \theta$