The correct option is A By the 12th century
The reign of Perumals came to an end by the 12th century. Consequently the chieftains, who were the local rulers, under the Perumals, began to rule their respective 'Nadus' independently. The reign under the control of a chieftain was known as 'Swapooram.' There were disparities in Wealth and military power among the Nadus.