2D → 3D shape analogy: Square : Cube :: Circle : ?

Introduction / Context:
Analogies may map a 2D figure to its standard 3D counterpart. A cube relates to a square (faces are squares); likewise, we select the 3D solid most directly corresponding to a circle.

Given Data / Assumptions:
Circle is a 2D curve; the canonical 3D analogue formed by revolution about a diameter is a sphere.

Concept / Approach:
Just as square → cube (3D extension), circle → sphere is the classic correspondence. Cone/cylinder use circular bases but are not the direct “circle → solid” counterpart in this canonical mapping.

Step-by-Step Solution:

Why Other Options Are Wrong:
Ellipse/parabola are 2D; cone/cylinder, while circular-based, are not the direct analogue in this standard pair.

Common Pitfalls:
Choosing cone/cylinder because they involve circles, missing the canonical circle → sphere mapping.

Final Answer:
Sphere