Answer
(b). ± $ \frac{\sin\theta}{\sqrt (1-\sin^{2}\theta)}$
Work Step by Step
From ratio identity-
$\tan\theta$ = $ \frac{\sin\theta}{\cos\theta}$
$\tan\theta$ = ± $ \frac{\sin\theta}{\sqrt (1-\sin^{2}\theta)}$
[From Pythagorean identity, $\cos\theta$ can be written as ± $\sqrt (1-\sin^{2}\theta)$]
Thus option 'b' is correct