Evaluate the Integral $\int \frac{6 \sin 2 x}{1+\cos ^{4} x} d x$

Multiple Choice

Evaluate the integral. $\int \frac{6 \sin 2 x}{1+\cos ^{4} x} d x$

A) $6 \arctan \left(\sec ^{2} x\right) +C$
B) $-6 \cos ^{2} 2 x+C$
C) $-6 \arcsin (\tan x) +C$
D) $1-6 \cos ^{2} x+C$
E) None of these