Solution:In the 18th century, Dhaka was a leading commercial centre that lost its importance. After The Battle of Plassey British became a strong economic power.Commercial cities such as Dhaka, Surat, and Masulipatnam declined when there is a shift to other places and when the British gradually gained political control in 1757 after the Battle of Plassey.
Colonial port cities such as Calcutta, Bombay and Madras, emerged rapidly as the new economic capitals and also became centres of colonial administration and political power. Therefore, the correct option is (c).