And let me tell you, LAST YEAR'S TOPPER OF UPSC KANISHKA KATARIA sir is a CS graduate. His OPTIONAL was MATHEMATICS. So if you will prepare hard as well as smart, then there is a high chance you will crack this exam.

Here I am attaching the list of optional subjects issued by Upsc. I hope that would help you.

1. History
2. Geography
3. Economics
4. Sociology
5. Public Administration
6. Philosophy
7. Psychology
8. Political Science
9. Agriculture
10. Animal Husbandry and Veterinary Science
11. Anthropology
12. Botany
13. Chemistry
14. Civil Engineering
15. Commerce
16. Electrical Engineering
17. Geology
18. Law
19. Mathematics
20. Management
21. Mechanical Engineering
22. Medical Science
23. Physics
24. Statistics
25. Zoology

All the best!

Cheers…!!!