Step 1: Social structure refers to the organised pattern of inter-relationships between persons and groups in a society, including the network of social positions, roles and institutions that hold a community together.
Step 2: Because the question describes exactly this pattern of relationships among people in a society, the correct term is social structure.
Step 3: Social psychology studies how individuals think, feel and behave in social settings, and social science is the broad academic field covering human society. The study of human inter-relationships itself is sociology. None of these names the pattern of relationships, so social structure is the answer.