Explanation: In the context of Indian geography and the Indian Ocean, it is important to understand the geographical relationships between various island nations and the Indian subcontinent. Sri Lanka is an island nation located off the southern coast of India, and it is surrounded by the Indian Ocean. The Maldives, another island nation, is located to the southwest of Sri Lanka, also in the Indian Ocean.
The Maldives is a collection of atolls and islands, forming a chain that stretches for hundreds of kilometers. It is the smallest country in Asia in terms of both land area and population. The Maldives and Sri Lanka share a maritime boundary and are both part of the broader Indian Ocean region. They are often considered island neighbours due to their proximity and the fact that they are both island nations.
Malaysia, on the other hand, is a Southeast Asian country that is not an island neighbour of Sri Lanka. It is located on the Malay Peninsula and the island of Borneo, which are geographically distant from Sri Lanka. Therefore, it is not a suitable answer for the question.
Maharashtra is a state in western India, located on the Indian subcontinent. It is not an island nation and is not a neighbour of Sri Lanka across the high seas. This option is incorrect because it does not fit the criteria of being an island nation and a neighbour of Sri Lanka.
In conclusion, the Maldives is the correct answer as it is an island nation located in the Indian Ocean, close to Sri Lanka, making it a natural island neighbour. This geographical relationship is significant in terms of maritime relations, trade, and cultural exchanges between the two nations.