Which of the following centres was famous for cotton trade in the Sangam period?

Internal trade was also brisk; caravans of merchants with carts and pack animals carried their merchandise from place to place and from fair to fair. Salt was an important commodity of trade, and salt-merchants moved with their families in carts provided with spare axles against contingencies. Barter played a large part in all transactions; honey and roots, for example, might be exchanged for fish-oil and toddy, and sugarcane and aval for venison and arrack, while in Musiri fish was sold for paddy. Agriculture was the mainstay of the national economy, and most of its operations were carried on by women of the lowest class (kadaisiyar) whose status appears to have differed little from that of the slave. The bulk of the land was owned by the vellalar, the agriculturists par excellence, who commanded a high social rank. The richer among them did not plough the land themselves, but employed labourers to do it. Besides owning land, they held official posts in the civil and military administration.