I want to know about most suitable Optional Subject for Civil Services examination organized by UPS

You can choose any subject as your optional subject in Civil Services examination organized by UPSC .. it is completely depends on your interest and ability to choose courses in Mains exam of Civil service

Here I am giving you information about optional subjects in Combined State Civil Services examination organized by Union public service commission..

List of Optional Subjects (Literature) - CS (Main) - (Total 26)
Arabic
Gujarati
Manipuri
Sanskrit
Assamese
Hindi
Nepali
Sindhi
Bengali
Kannada
Oriya
Tamil
Chinese
Kashmiri
Pali
Telugu
English
Konkani
Persian
Urdu
French
Marathi
Punjabi
German
Malayalam
Russian

List of Optional Subjects - CS (Main) - (Total 25)
Agriculture
Management
Animal Husbandry & Vetinary Science
Mathematics
Anthropology
Mechanical Engineering
Botany
Medical Science
Chemistry
Philosophy
Civil Engineering
Physics
Commerce & Accountancy
Political Science & International Relations
Economics
Psychology
Electrical Engineering
Public Administration
Geography
Sociology
Geology
Statistics
Indian History
Zoology
Law