In the analogy "Car : road :: ship : ____", which medium of travel correctly completes the pair?

Introduction / Context:
This analogy checks your understanding of the natural or usual medium in which different vehicles travel. A car is typically driven on a road. In the same way, a ship has its own medium of movement. Choosing the correct option requires knowledge of basic transportation modes and the environment they use.

Given Data / Assumptions:

• First pair: car and road.
• Second pair: ship and an unknown medium.
• Options: water, air, road, both air and water, space.
• We consider the standard use of each vehicle, not special cases.

Concept / Approach:
A car operates primarily on roads and highways built on land. This establishes a pattern of "vehicle : typical medium of movement". A ship is a large watercraft designed to travel on seas and oceans or larger rivers and lakes. Therefore, the correct medium for a ship is water. Air and space are relevant for planes and spacecraft, but not for ordinary ships. "Road" is obviously incorrect for a ship.

Step-by-Step Solution:

Step 1: Recognise that a car moves on a road, so the relation is "vehicle : where it travels". Step 2: Identify a ship as a water based transport vehicle. Step 3: Recall that ships sail on seas, oceans, and sometimes large rivers, all of which are bodies of water. Step 4: Choose water as the medium that matches the pattern of the first pair. Step 5: Confirm that no other option fits better than water for this standard relationship.

Verification / Alternative check:
Air is used by aeroplanes and helicopters, not by ships. Roads are used by cars, buses, trucks, and motorcycles, and not by ships. "Both air and water" is more suitable for special amphibious vehicles, not standard ships. Space is used by spacecraft and satellites. Only water corresponds directly to the normal environment in which a ship travels.

Why Other Options Are Wrong:
Selecting air, road, both air and water, or space confuses different types of vehicles and their typical operating domains. Since the analogy relies on the most common and straightforward association, only water is correct for a ship. The other options do not match the simple and widely known relationship given in the question.

Common Pitfalls:
Occasionally, candidates may overthink by considering rare or specially designed vehicles or by reading too much into the option "both air and water". However, in standard reasoning questions, you should always assume typical everyday vehicles and their usual modes of travel unless stated otherwise.

Final Answer:
The analogy is completed as "Car : road :: ship : water".