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

https://clay6.com/mpaimg/772_a.jpg

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