Indian physiography: Identify the range forming the watershed (divide) between India and Myanmar. Name the primary mountain/hill system that marks the drainage divide along the Indo–Myanmar border. Choose the correct option.

Concept

• A watershed/divide separates drainage basins.
• Along the Indo–Myanmar frontier, the Patkai Bum (Patkai Hills) form the key watershed, with associated ranges like the Naga Hills extending nearby.

Why not others?
Arakan Yoma lies mostly inside Myanmar parallel to the coast; Garo–Khasi–Jaintia are in Meghalaya; “Naga Hills only” is incomplete compared with the broader Patkai system.

Final Answer
Patkai Bum (Patkai Hills).