Final answer:
The answer is option A. The statement that African civilizations before 1901 exhibited diverse and rich cultural characteristics is supported by evidence of varied cultures, political states, trade networks, proto-state societies, and advancements in societal organization.
Step-by-step explanation:
The correct statement about the civilizations of Africa before 1901, best inferred by the information provided, is A) They exhibited diverse and rich cultural characteristics. Evidence from the given texts indicates that Africa was a continent with a tremendous diversity of cultures, languages, political states, and trade networks. This diversity can be seen in the small village-based structures as well as large kingdoms ruled by kings, all having different governmental organizations, societal rules, economic systems, religions, and artistic expressions. The presence of extensive trade networks within Africa and between Africa, Europe, and Asia demonstrates that these civilizations were far from isolated. Furthermore, the notions of proto-states among certain African societies such as the Asante and Zulu, along with the development of state bureaucracies, laws, and monumental architecture, suggest a high level of societal organization.