What is \(\frac{{{\rm{co}}{{\rm{s}}^4}{\rm{A}} - {\rm{\;si}}{{\rm{n}}^4}{\rm{A}}}}{{{\rm{co}}{{\rm{s}}^2}{\rm{A}} - {\rm{\;si}}{{\rm{n}}^2}{\rm{A}}}}\) equal to?

• A. cos2A - sin2A
• B. cosA - sinA
• C. 1
• D. 2