Subjects typically preferred by candidates for optional papers in the UPSC exam include Geography, Public Administration, Political Science, and Sociology. These subjects attract aspirants due to their relevance in both general studies and the examination's core themes. Geography is appreciated for its scientific approach and applicability to current affairs, while Public Administration aligns closely with governance principles. Political Science offers insights into political systems, which is critical for civil services. Sociology's focus on societal structures provides candidates with a broader understanding of human interactions and behaviors essential in public service.