The Indus Valley Civilization, one of the world's oldest, spanned present-day India and Pakistan. Key sites include Mohenjodaro and Harappa (in Pakistan) and Lothal (in Gujarat, India). Lothal is notable for its ancient dockyard and maritime trade. Ahar is an unrelated archaeological site. Final Answer: \[ \boxed{\text{The correct answer is (3) Lothal.}} \]