Step 1: Use the Formula for Area.
The area of a loop formed by the curve \( y = \sin \theta \) can be computed using integration. The total area enclosed by the curve is \( \frac{\pi a^2}{24} \), based on the specific geometry of the curve.
Step 2: Conclusion.
The correct answer is (B), \( \frac{\pi a^2}{24} \).