hi,

see upsc syllabus is designed as a unique way and students from any branch of studies may prepare for it. however you must be very dedicated towards your study and analyse the syllabus carefully. however there is 25 optional subjects of various discipline and 23 literature subjects of different language in available. from arts stream subjects are available apart from literature is history, economics, geography, law, philosophy, political science and international relation, psychology, public administration, sociology.  however the preparation can not be done quickly which of the subject you may choose. at least of 1 years sincere studies needed to crack the exam.