The correct answer to the question is option 3, Lothal. Lothal is a Harappan site located in present-day Gujarat, India. It was an important port and trading center during the Indus Valley Civilization. Archaeological excavations at Lothal have revealed a well-developed dockyard. The dockyard at Lothal consisted of a basin or a tank, which was connected to the river through a channel or a drain. The main purpose of the dockyard was to facilitate trade and maritime activities. Ships and boats would have been able to access the dockyard through the channel, allowing for the movement of goods and people. The presence of a dockyard at Lothal indicates the advanced engineering skills and organization of the Harappan civilization.