which subjects to choose for ca final exams


14 May 2017  
my exams are due this nov. for final group 2
i have not yet started study for same as recently appeared for group one
i am thinking to prepare as per the strategy that i will give two exams this attempt and then 2 next
however if i get time i will appear for all
so i want to know whether to choose cost and isca as a combination or idt and isca ?
reason of asking
i have to get exemption this time and then have to score only 40 marks each in next attempt
gst is due in may 18 that's why i m thinking to give IDT in may instead of this attempt
however i think dt and idt together is typical combination , and its hard to score exemption in AMA/cost
please suggest ur views