Solve the equation on the interval $0 \leq \theta<2 \pi$. \[ \cos (2 \theta)=\frac{\sqrt{3}}{2} \] What are the solutions to $\cos (2 \theta)=\frac{\sqrt{3}}{2}$ in the interval $0 \leq \theta<2 \pi$ ? Select the correct choice and fill in any answer boxes in your choice below. A. The solution set is \{\} . (Simplify your answer. Type an exact answer, using $\pi$ as needed. Type your answer in radians. Use integers or fractions for any numbers in the expression. Use a comma to separate answers as needed.) B. There is no solution.

Step 1 ：The given equation is in the form of \( \cos (2 \theta)=\frac{\sqrt{3}}{2} \).

Step 2 ：We know that the cosine function has the value of \( \frac{\sqrt{3}}{2} \) at \( \frac{\pi}{6} \) and \( \frac{11\pi}{6} \) in the interval \( 0 \leq \theta<2 \pi \).

Step 3 ：However, the angle in the cosine function is \( 2\theta \) not \( \theta \). So, we need to solve the equations \( 2\theta = \frac{\pi}{6} \) and \( 2\theta = \frac{11\pi}{6} \) to find the values of \( \theta \) in the interval \( 0 \leq \theta<2 \pi \).

Step 4 ：The solutions to the equations \( 2\theta = \frac{\pi}{6} \) and \( 2\theta = \frac{11\pi}{6} \) are \( \theta = \frac{\pi}{12} \) and \( \theta = \frac{11\pi}{12} \) respectively.

Step 5 ：These are the solutions to the original equation \( \cos (2 \theta)=\frac{\sqrt{3}}{2} \) in the interval \( 0 \leq \theta<2 \pi \).

Step 6 ：Final Answer: The solution set is \( \boxed{\left\{\frac{\pi}{12}, \frac{11\pi}{12}\right\}} \).