@sat_009I in particular don't have my graduation subject as Optional. Could go by that and add Anthro provided a unique opportunity to study humans in an objective way. Moreover, materials available and good results in recent past. Culmination of multiple favourable factors made me pursue Anthro.
Radcliffe's Brown being a structural functionalists speaks about kinship as a social structure and being the social reality. He suggested to study kinship as an institution to understand relation and how it guides behavior in the society. It is to say kinship works as a unit to control social relations through behavior. Ex - Joking relationship,etc.
Levi Strauss do not consider social institution as social reality. He merely sees them as social construct and focusses on the relationship between each element. He propounded the Alliance Theory, where he suggest kinship is nothing but an exchange of wives in a recurrent marriage order. Further in his Elementary Structure of Kinship he gave a detailed explanation of how it works. In it he talks about the open and closed system of alliance making.