Final answer:
True Gold mines were indeed central to the economy of medieval African cities such as Timbuktu and Gao in the Mali Empire, which played a significant role in trans-Saharan trade.
Step-by-step explanation:
The statement that gold mines were central to the economy of a medieval African city is true, and the city in question is often associated with the Mali Empire, particularly Timbuktu. Gold was a principal commodity for several empires in Africa, including Ghana and Mali, which controlled trade routes and utilized gold to solidify their power.
For instance, the Mali Empire benefitted immensely from the trans-Saharan trade, where gold and salt were significant products. The rulers of Mali, by controlling gold-mining towns and trade routes, ensured that the empire thrived economically.
Additionally, cities like Gao and Djenné also prospered due to their involvement in this bustling trade network.