Geometry

Question Analysis
This question tests recognition of frustums.
The main focus is identifying truncation.

Key Concept Explanation
Frustum: Cone with top sliced parallel to base → two parallel circles.
Key differences:
Full cone (A): No truncation
Oblique cone (B): Tilted but complete
Double cone (D): Two apexes

Step-by-Step Solution
Eliminate A (complete cone) and B (tilted but whole).
Eliminate D (hourglass shape ≠ frustum).
Select C (flat top parallel to base).

Common Mistakes
Choosing...