Which of the following focuses solely on human interactions and political systems?

The focus of political science is primarily on the study of political systems, governance, and human interactions within political contexts. This discipline examines how power is distributed and exercised, the roles of institutions, political behavior, and public policy. Political scientists analyze governments, political parties, and elections, along with the impact of political decisions on societies.

In contrast, sociology encompasses a broader study of social behavior and the structures that shape human society, including family, education, and social institutions. Anthropology focuses more on the cultural and evolutionary aspects of humans, including their artifacts, traditions, and social practices. Psychology, while concerned with human behavior, focuses on the individual and mental processes rather than the systemic interactions specific to political systems.

Therefore, political science is the most appropriate choice for studying human interactions specifically related to governance and political structures.