Association – identify the most appropriate category/domain: Engine, compartment, and wheels are most closely associated with which of the following?

Introduction / Context:
This item tests recognition of functional association. “Engine, compartment, wheels” together cue a particular transportation system. We must choose the domain that naturally fits all three simultaneously.

Given Data / Assumptions:

• Engine: locomotive (rail) or engine (generic) but strongly evokes trains when paired with “compartment.”
• Compartment: passenger coach section typically in trains.
• Wheels: present in many vehicles, but in combination with “engine” and “compartment,” it suggests rail stock.

Concept / Approach:
Look for a unifying transport context. “Engine + compartment” is classic railway vocabulary. Wheels further support rolling stock. The best answer is the infrastructure that such stock runs on: the rail-line. A ship/sea pairing belongs to maritime transport, which does not use compartments in the rail sense nor track-bound wheels.

Step-by-Step Solution:

Verification / Alternative check:

Why Other Options Are Wrong:

• Motor: Too generic; not a domain.
• Ship/Sea: Maritime context; no rail compartments or track wheels.
• Airstrip: Aviation; unrelated to compartments and rail-bound wheels.

Common Pitfalls:
Over-focusing on an individual word (e.g., “engine”) and ignoring the combined signal of “compartment.” Always synthesize all cues.

Final Answer:
Rail-line