The sum of all values of \(\theta \in \left( {0,\frac{\pi }{2}} \right)\) satisfying \({\rm{si}}{{\rm{n}}^2}\;2\theta + {\rm{co}}{{\rm{s}}^4}\;2\theta = \frac{3}{4}\) is:

• A. π
• B. 5π/4
• C. π/2
• D. 3π/8