Answer : 2. "तमिलनाडु"
Explanation :

1. Palk Strait is a strait between the Indian state of Tamil Nadu and the Mannar district of the Northern Province of Sri Lanka.

2. This strait connects the Bay of Bengal to the Palk Bay in the north-east and then to the Gulf of Mannar in the south-west.

3. The strait that separates India and Sri Lanka is the Palak Strait.