The value of the determinant \(\left| {\begin{array}{*{20}{c}} {{{\cos }^2}\frac{\theta }{2}}&{{{\sin }^2}\frac{\theta }{2}}\\ {{{\sin }^2}\frac{\theta }{2}}&{{{\cos }^2}\frac{\theta }{2}} \end{array}} \right|\) for all values of θ, is

• A. 1
• B. cos θ
• C. sin θ
• D. cos 2θ