The correct option is North-West.
Explanation
The Indian subcontinent is physically demarcated from the rest of Asia by a continuous chain of mountain ranges. These ranges form a natural frontier in the north, north-east, and north-west directions.
Geographical Analysis:
- The Sulaiman Range is located primarily in Pakistan, to the west of the Indus River.
- It extends southwards from the syntaxial bend of the Himalayas and the Hindu Kush mountains.
- Along with the Kirthar Range to its south, the Sulaiman Range forms the North-Western boundary of the Indian subcontinent.
- These ranges separate the Indian subcontinent from the Iranian Plateau and the Afghan borderlands.
Key Takeaway: The Sulaiman and Kirthar ranges define the North-Western frontier of the Indian subcontinent, acting as a barrier between the subcontinent and the Iranian Plateau.