As you requires I am here giving you syllabus for Bihar Public Service Commission (BPSC) Pre exam and list of optional subjects for Main exam.

Syllabus of Preliminary BPSC exam:
Syllabus of Preliminary Examination contain following topics:

General Knowledge
English
Mathematics

General Knowledge
Current events of national and international importance
History of India and Indian National Movement
Indian and World Geography
Indian Polity and Economy
General Mental Ability Questions

English
Spotting the Errors
Antonyms and Synonyms
Filling in the blanks
Use of prepositions, idioms/phrases
Word analogies
Test of spellings
Re-arranging jumbled up sentences
Comprehension of passage and answering questions based on the passage

Mathematics
Algebra
Linear Algebra
Calculus
Trigonometry
Analytic Geometry
Ordinary Differential Equations
Dynamics, Statics and Hydrostatics
Vector Analysis
Real Analysis
Complex Analysis
Partial differential equations

Optional Subjects (any 2):
Mathematics
Mechanical Engineering
Physics
Chemistry
Civil Engineering
Geology
Statistics
Zoology
Economics
Agriculture