Answer:
The correct answer is option D. "its salt and gold trade".
Explanation:
Timbuktu is an ancient city in Mali, located in the north of Nile River. Timbuktu is best known for its salt and gold trade since it became a permanent settlement in the early 12th century. Actually, before becoming part of the Mali Empire, Timbuktu was already a trade center of salt, gold, ivory, and slaves. This ancient city was the southern terminus of the important trans-Saharan trade route.
