No, you cannot choose just any optional subjects for CSS exams. There is a predefined list of optional subjects provided by the Federal Public Service Commission (FPSC) from which you can make your selections. The FPSC releases an updated syllabus each year, specifying the optional subjects available for that particular exam cycle.
The list of optional subjects covers a wide range of disciplines, including humanities, social sciences, natural sciences, and professional fields. Some common optional subjects include English Literature, History, Political Science, International Relations, Psychology, Sociology, Economics, Law, Physics, Chemistry, Mathematics, and Computer Science, among others.
In order to select optional subjects for the CSS examination, candidates must choose from the list of 7 groups provided by the Federal Public Service Commission (FPSC), which offer subjects of either 100 or 200 marks.