Analogy — Shape transformation by rotation: Square : Diamond :: Circle : ____

Introduction / Context:
A “diamond” in common parlance is a square rotated by 45 degrees; rotation does not change the essence of the square, only its orientation/appearance. A circle rotated remains the same — i.e., round. Thus the mapping is “shape rotated → percept remains identical” for the circle.

Given Data / Assumptions:

• Square ↔ diamond (same shape, rotated).
• Circle rotated is still round.

Why Other Options Are Wrong:

• Oval — implies scaling/distortion, not pure rotation.
• Smooth/Silver — unrelated properties.

Final Answer:
Round