$$\left( {x + \frac{1}{x}} \right)$$ $$\left( {x - \frac{1}{x}} \right)$$ $$\left( {{x^2} + \frac{1}{{{x^2}}} - 1} \right)$$$$\left( {{x^2} + \frac{1}{{{x^2}}} + 1} \right)$$is equal to ?

• A. ${x^6} - \frac{1}{{{x^6}}}$$
• B. ${x^8} - \frac{1}{{{x^8}}}$$
• C. ${x^6} + \frac{1}{{{x^6}}}$$
• D. ${x^8} + \frac{1}{{{x^8}}}$$