If you have no prior knowledge of it then I will advise you to go through some online books and notes of philosophy e.g. Copi's or Hurley's books on Logic and philosophies of Muslims and Western philosophers, then you will be in a better position to take decision but be careful! Never Never Never decide in hurry after reading just one page of first chapter. Better to do thorough analysis of each and every chapter to find whether you can digest it or not because you can't get good marks in CSS Exams without deep understanding of contents of subjects.

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"And whoever puts all his trust in ALLAH, He will be enough for him" (Al-Quran 65:1)