Correct option is (C) \(-\cot x-\tan x+c\)
\(\int \frac{\cos 2 x}{\cos ^{2} x . \sin ^{2} x} d x\)
\(= \int \frac{\cos^2x - \sin^2 x}{\cos^2 x.\sin ^2 x}dx\)
\(= \int \left(\frac 1{\sin^2 x} - \frac 1{\cos^2 x}\right)dx\)
\(= \int \text{cosec}^2x dx- \int \sec^2 x dx\)
\(= - \cot x - \tan x + c\)