Answer:
D) cultural anthropology
Step-by-step explanation:
Cultural anthropology is a branch of anthropology which deals with the study of how people developed cultural systems, and the influence the cultural systems have on their way of life and their environment. It involves the study of the evolution of the cultures of people and their society over time.
We can infer that Audrey Richards was working on cultural anthropology, as his focus is on the ethnography of the coming-of-age rituals of the Bemba. This clearly takes a look at the culture of the Bemba people, and how their way of life evolved, and influences their lifestyle.