Dear seniors,
I am a new aspirant of CSS. I have selected following subjects as optional:
1. Business Administration
2. Islamic history
3. Sindhi
4. Philosophy
5. Sociology

I have a confusion that I have not selected any subject from group 2 of science whereby physics, stat and chemistry are included. There reason behind skipping these subject is my competency in the mentioned subjects. Is it mandatory to choose a subject from each group or I do not need to worry for the decision?

Moreover, I would like to have book recommendations for the above mentioned subjects.

Thank you in advance for responses and time.