$\angle C=90^{\large\circ}$
$\angle A+\angle B=90^{\large\circ}$
$\Rightarrow \tan A.\tan B =1$
$\tan B=\large\frac{1}{\tan A}$
$\tan A$ and $\tan B$ are roots
$(x-\tan A)(x-\tan B)$
$\Rightarrow x^2-(\tan A+\tan B)x+\tan A\tan B$
$\Rightarrow x^2-(\tan A+\tan B)x+1$
$\tan A+\tan B=\tan A+\large\frac{1}{\tan A}=\frac{2\tan^2+1}{2\tan A}=\frac{2}{\sin 2A}$
$\sin 2A=\large\frac{2\tan A}{1+\tan^2A}$
$\Rightarrow x^2-\large\frac{2}{\sin 2A}$$x+1$
Hence (A) is the correct answer.