Classification — countries and capitals: select the pair that is NOT a correct country–capital match.

Introduction / Context:
Three pairs correctly map a country to its capital city. One pair mismatches a country with another sovereign nation (not a capital).

Given Data / Assumptions:

• Taiwan : Taipei → correct.
• Iran : Tehran → correct.
• Japan : Tokyo → correct.
• China : Mongolia → incorrect; the capital of China is Beijing; Mongolia is an independent country whose capital is Ulaanbaatar.

Concept / Approach:
Confirm each country’s capital; the sole mismatch is the odd pair.

Step-by-Step Solution:

Verification / Alternative check:
Capitals list confirms Beijing (China), Ulaanbaatar (Mongolia).

Why Other Options Are Wrong:
They are accurate country–capital pairs.

Common Pitfalls:
Confusing neighboring states with capitals.

Final Answer:
China : Mongolia