A block is kept on a frictionless inclined surface with angle of inclination $\propto$. The incline is given an acceleration $a$ to keep the block stationary. Then $a$ is equal to : <br>

Question

( A ) $g \; \tan \propto$
( B ) $g / \tan \propto$
( C ) $g$
( D ) $g \; \mathrm{cosec} \propto$