Explanation:

- Daman and Diu: This Union Territory is actually merged with Dadra and Nagar Haveli but historically, it had a high population density due to its small area and large population.

- Dadra and Nagar Haveli: Another small territory that historically had a high population density compared to larger landmasses.

- Andaman and Nicobar Islands: These islands have vast areas of forest and relatively low population density. Correct Answer.

- Puducherry: This is a densely populated UT, given its smaller area and settlement.