Final answer:
Ethiopia was the most affected by Christianity from 1200 to 1450, maintaining a robust Christian identity and developing an artistic Christian tradition with rock-hewn churches and religious exchanges.
Step-by-step explanation:
Among the African states listed, C) Ethiopia was the most affected by Christianity during the period from 1200 to 1450. Ethiopia, the successor of the ancient Kingdom of Aksum, maintained a strong Christian identity during this time. The Christian Kingdom of Aksum was an early adopter and significant center of Christianity in Africa. Ethiopian rulers constructed rock-hewn churches and engaged in religious and political exchanges with European powers such as Italy.
In contrast, kingdoms such as Mali and Ghana in West Africa were predominantly influenced by Islam, which spread through military conquest, trade, and cultural interactions. Great Zimbabwe, located in Southern Africa, had its own religious system and was not notably influenced by Christianity or Islam during this period.