(1) $a=g \cos \theta$

(2) $a=\frac{g}{\sin \theta}$

(3) $\mathbf{a}=\frac{\mathbf{g}}{\operatorname{cosec} \theta}$

(4) $a=g \tan \theta$

Solution:

Answer is (4)

In non-inertial frame we have,

$N \sin \theta=m a$

$N \cos \theta=m g \quad \ldots$ …(ii)

$\tan \theta=\frac{a}{g}$

$\mathrm{a}=\mathrm{g} \tan \theta$