The Ten Degree Channel separates the Andaman and Nicobar Islands from each other. Therefore, the correct option is A, "Andaman and Nicobar."

The Andaman and Nicobar Islands are a group of islands in the Bay of Bengal, and the Ten Degree Channel is a narrow strait that runs between the southernmost islands of the Nicobar group and the northernmost islands of the Andaman group.

Option B ("Nicobar and Sumatra") is incorrect because Nicobar is part of the Andaman and Nicobar Islands and is not separated from them by the Ten Degree Channel. Sumatra is located south of the Ten Degree Channel.

Option C ("Maldives and Lakshadweep") is also incorrect because these two island groups are located far away from each other in the Arabian Sea and are not separated by the Ten Degree Channel.

Option D ("Sumatra and Java") is also incorrect because these two islands are located next to each other and are not separated by the Ten Degree Channel.