Consider the following pairs

River	Flows into
1. Mekong	Andaman Sea
2. Thames	Irish Sea
3. Volga	Caspian Sea
4. Zambezi	Indian Ocean

Which of the pairs given above is/are correctly matched?

The correct option is 3 and 4 only.

Let us analyze each pair step-by-step to understand why they are correctly or incorrectly matched:

1. Mekong - Andaman Sea (Incorrect):
The Mekong River is one of the longest rivers in Southeast Asia. It flows through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam, and empties into the South China Sea (specifically the Mekong Delta), not the Andaman Sea.

2. Thames - Irish Sea (Incorrect):
The River Thames is the longest river entirely in England. It flows through London and empties into the North Sea on the eastern coast of Great Britain, not the Irish Sea.

3. Volga - Caspian Sea (Correct):
The Volga River is the longest river in Europe and flows through Central Russia. It drains into the closed basin of the Caspian Sea.

4. Zambezi - Indian Ocean (Correct):
The Zambezi is the fourth-longest river in Africa. It flows through several countries in southern Africa, including Zambia, Angola, Namibia, Botswana, Zimbabwe, and Mozambique, before emptying into the Indian Ocean.

Therefore, only pairs 3 and 4 are correctly matched.