Answer:
Ethnogenesis.
Explanation:
Ethnogenesis may be defined as the development and formation of the ethnic group. The inside and outside identification is important for the development of ethnogenesis.
Hutu and Tutsi considerd and treated unequally from each other. Earlier, they were considered a single group of people. Tutsi become superior farmer than Hutu. On the basis of ethnogenesis, they will see each other as different. Ethnogenesis includes the development of new emergence of social group and can be identify as cohesive identity.
Thus, the answer is ethnogenesis.