Answer : 4. "Ten Degree Channel"
Explanation :

1. The Ten Degree Channel separates the Andaman Islands and Nicobar Islands from each other.

2. It is located on the 10-degree line of latitude, north of the equator.

3. Channel is a wide open waterway that passes through two landmasses that are located close to each other.

Other waterways separating the Andaman and Nicobar Islands include.

A. Duncan Waterway: It separates South Andaman and Little Andaman.

B. Grand Channel: It separates Great Nicobar and Sumatra island of Indonesia.

C. Coco Strait: It separates North Andaman and Coco Islands of Myanmar.