Geometry

Question Analysis
This question tests the geometric definition of a right cone versus an oblique cone.
The main focus is on understanding the orientation of the height.

Key Concept Explanation
The height of a cone is the perpendicular distance from the apex to the base.
In a right cone, this line is perpendicular.
In an oblique cone, the height does not intersect the center of the base directly.

Step-by-Step Solution
Option A: Incorrect. Right cones have circular bases.
Option B: Incorrect. It is both true for right cones and oblique cones, so it can not distinguish them.
Option C: Correct. Perpendicular distance from the apex to the base is a key characte...