You haven't mentioned in which subjects have you done your B.Sc in. Ideally, Prelims has 2 Papers namely General Studies and CSAT.

General Studies has Current Events, History of India and Indian National Movement, Indian and World Geography, Indian Polity and Governance, Economic and Social Development, Environmental Ecology, Biodiversity and Climate Change and General Science.

CSAT has Comprehension, Interpersonal skills including communication skills, Logical Reasoning and Analytical ability, Decision making and problem solving, General Mental Ability, Basic numeracy and Data Interpretation.

From now on, you need to study only for 1 Optional subject instead of 2. So you can take up any one of the subjects that you have studied in your B.Sc. Alternatively if you can help us with the subjects you have studied, we can help you pick the Optional subject. Optional subject should be chosen based on your interest. You should be able to get the material handy and also it should have btter scope in case things with UPSC dont work. So please do help us with the subjects you studied in your B.Sc and we shall help you accordingly.