Scoring high will make you able to get allocation in FSP which entirely depends on your combination of subjects as there remained a variation in scoring trends each year in CSS exams. So make a combination of subjects which score well.
It will be good if you give your academic background here or major subjects in graduation for combination assessment. All these subjects needs much effort for getting high score. Your stated combination can benefit you if all subjects are grasped extraordinarily, go with it if you are confidant enough for commanding all these subjects and keeping your educational background in mind.. I am giving you some suggestions here:
International Law is fine
Try to replace Business Ad with journalism or regional language
Try to put psychology in place of British history or zoology keeping your academics as well interest.

Further queries are appreciated.

Regards,