The correct answer is: a) The rise of independent feudatory states.
The Vijayanagara Empire was a Hindu empire that ruled over much of southern India from the 14th to the 16th centuries. It was founded by Harihara I and Bukka Raya I, two brothers who were generals in the Hoysala army. The empire reached its peak under the rule of Krishnadevaraya, who reigned from 1509 to 1529.
The Vijayanagara Empire declined in the 16th century due to a number of factors, including internal conflicts, external invasions, and economic problems. The empire finally collapsed in 1565, after being defeated by a coalition of Muslim sultanates.
The decline of the Vijayanagara Empire led to the rise of a number of independent feudatory states. These states were often at war with each other, which led to political instability and economic decline in the region.
Option b) is incorrect because the Vijayanagara Empire was not completely taken over by a colonial power. Option c) is incorrect because the decline of the Vijayanagara Empire did not lead to a power vacuum. Option d) is incorrect because the decline of the Vijayanagara Empire did not lead to the unification of Tamil kingdoms.