Answer:
It was an East African city-state that grew rich from trade and taxes.
Step-by-step explanation:
Kilwa is known for being an island and an independent city-state that is situated around the coast of East Africa. It was popular for its trading activities between the twelfth and fifteenth centuries, particularly from gold trades and exchange. It serves as a window between east Africa and the Arabian and Asian nations, particularly Persian and India. It is located in present-day Tanzania.
Hence, in this case, the correct answer is: Kilwa was an East African city-state that grew rich from trade and taxes.