Analogy — “Fan : Wings” (blades). Choose the pair where the second term is a key part/component of the first.

Introduction / Context:
In everyday usage, the “wings” of a fan refer to its blades — an essential component. The analogy therefore encodes a whole-to-part (object → key component) relation. We must identify a wheel’s comparably essential part.

Given Data / Assumptions:

• “Fan : Wings” uses “wings” to mean blades.
• We need “wheel : (its component).”
• Only one option should be a true part rather than a property or action.

Concept / Approach:
Distinguish between component, property (shape), action (what it does), and container/association.

Step-by-Step Solution:

Verification / Alternative check:
In standard mechanical description, spokes are integral wheel parts; tyres are separate fitted covers.

Why Other Options Are Wrong:
They do not express a clean whole-to-part relation.

Common Pitfalls:
Confusing properties or accessories with true constituent parts.

Final Answer:
Spokes