Palk Strait is a stretch of water that lies between two countries. Option 1, India & Pakistan, is incorrect because the Palk Strait is not between these two countries. Option 2, Pakistan & Sri Lanka, is also incorrect because Pakistan is not one of the countries that border the Palk Strait. Option 3, India & Sri Lanka, is the correct answer. The Palk Strait separates the southernmost tip of India (Tamil Nadu) from the northernmost part of Sri Lanka. Option 4, Pakistan & Iran, is incorrect as neither of these countries shares a border with the Palk Strait. It is important to note that the Palk Strait is a significant waterway for shipping and has historical and cultural importance for both India and Sri Lanka.