If $A=\cos^2\theta+\sin^4\theta$ then for all value of $\theta$

Question

$\begin{array}{1 1}(a)\;1\leq A\leq 2&(b)\;\large\frac{3}{4}\normalsize\leq A\leq 1\\(c)\;\large\frac{13}{16}\normalsize\leq A\leq 1&(d)\;None\;of\;these\end{array}$