As answered in your earlier query, you can think of any of these two. In Hindi medium, Geography as well as Political Science and International Relations are really good optional subjects and candidates have scored good marks and have succeeded in Civil Services Examination.
As Geography is your own subject, you can consider keeping Geography as optional subject. When it comes to standard text-books, study materials as well as quality guidance you have a wide choice available in Hindi as well.
Before you decide, have a look at the syllabus and previous years’ question papers to understand the examiner’s expectations and current trends.
Commence preparation and make a move towards your goal – career in ‘Civil Services’.
All the best!