The correct answer is option 2, Lothal. Lothal is believed to have had direct sea trade links with Mesopotamia, which is present-day Iraq. This is supported by various archaeological findings, such as the discovery of a dockyard in Lothal, which indicates its involvement in maritime activities. Additionally, artifacts imported from Mesopotamia, such as pottery and seals, have been found in Lothal. The presence of these imported goods suggests a direct trade relationship between the two regions. Therefore, Lothal is considered to be an important site for understanding the trade and cultural exchange between the Harappan civilization and Mesopotamia.