Answer: b) Cultural anthropology
Explanation:
Cultural anthropology is defined as the field of anthropology in which human interaction and shaping within societies, environment and culture is studied. Development, present society, past culture, tradition, languages, customs etc happening in environment and their differences is known.
According to the question, Richard is working in cultural anthropology department for studying upcoming and past ritual of Bemba along with their food, health of people .
Other options are incorrect because archeology and physical anthropology are not the field where human culture, society and developed is researched.Thus, the correct option is option(b).