If \( f(\theta)=\sin ^{4} \theta+\cos ^{2} \theta \), then range of...

If \( f(\theta)=\sin ^{4} \theta+\cos ^{2} \theta \), then range of \( f(\theta) \) is
(a) \( \left[\frac{1}{2}, 1\right] \)
(b) \( \left[\frac{1}{2}, \frac{3}{4}\right] \)
\( \mathrm{P} \)
W)
(c) \( \left[\frac{3}{4}, 1\right] \)
(d) None of these