Explanation:

- Kalibangan: Located in present-day Rajasthan, India, it was an important agricultural and trade center of the Indus Valley Civilization. It is not known as a port city.

- Rakhigarhi: Situated in present-day Haryana, India, Rakhigarhi is one of the largest Harappan sites but not recognized as a port city.

- Dholavira: Found in Gujarat, India, it was a major urban center but primarily inland, and is not considered a port city.

- Lothal: ?? Located in present-day Gujarat, India, Lothal is widely recognized as a port city due to its dockyard and evidence of maritime trade.

Correct Answer: Lothal