
Step 1: Analyze the given 3D hollow geometry (Figure D). It consists of six triangular faces and nine equal edges, forming a symmetrical structure.
Step 2: Identify which given net diagrams (P, Q, R, S) can be folded along the dotted lines to form the described 3D shape.
- Option P: Contains six triangles arranged in a way that they can be folded into a symmetrical 3D figure.
- Option Q: Also consists of six triangles correctly placed for forming the shape.
- Option R: Maintains the same triangular face count and edge arrangement, making it valid.
- Option S: The triangular faces are not arranged correctly to form the required 3D structure.
Step 3: Since P, Q, and R can be folded into the required 3D shape, the correct answer is:
\[ \text{P, Q, and R} \] Thus, the correct answer is option C.





Let $ P(x_1, y_1) $ and $ Q(x_2, y_2) $ be two distinct points on the ellipse $$ \frac{x^2}{9} + \frac{y^2}{4} = 1 $$ such that $ y_1 > 0 $, and $ y_2 > 0 $. Let $ C $ denote the circle $ x^2 + y^2 = 9 $, and $ M $ be the point $ (3, 0) $. Suppose the line $ x = x_1 $ intersects $ C $ at $ R $, and the line $ x = x_2 $ intersects $ C $ at $ S $, such that the $ y $-coordinates of $ R $ and $ S $ are positive. Let $ \angle ROM = \frac{\pi}{6} $ and $ \angle SOM = \frac{\pi}{3} $, where $ O $ denotes the origin $ (0, 0) $. Let $ |XY| $ denote the length of the line segment $ XY $. Then which of the following statements is (are) TRUE?