The value of $$\sec^4 \theta (1 - \sin^4 \theta) - 2 \tan^2 \theta$$ is:

$$\sec^4\theta(1-\sin^4\theta)-2\tan^2\theta=\sec^4\theta\ -\sec^4\theta\ \sin^4\theta\ -2\tan^2\theta\ $$

$$=\sec^4\theta\ -\frac{\sin^4\theta}{\cos^4\theta\ }\ -2\tan^2\theta\ $$

$$=\sec^4\theta\ -\tan^4\theta-2\tan^2\theta\ $$

$$=\left(\sec^2\theta\ +\tan^2\theta\ \right)\left(\sec^2\theta\ -\tan^2\theta\ \right)-2\tan^2\theta\ $$

$$=\left(\sec^2\theta\ +\tan^2\theta\ \right)\left(1\right)-2\tan^2\theta\ $$

$$=\sec^2\theta\ +\tan^2\theta\ -2\tan^2\theta\ $$

$$=\sec^2\theta\ -\tan^2\theta\ $$

$$=1$$

Hence, the correct answer is Option B