If you choose B1/A1 you will no longer be considered as subsidized patient and will be paying as private patient. Subsidized patients can choose ward B2/C. You can go admissions office to book a ward once you’re above 37 weeks. If havent reached 37 weeks at least, they will ask you to come back. Note that your booked class may not be available on the day you admitted, they will give whats available first and transfer you once your ward of choice is available.
They won’t allow u to book the bed.. it will only be done on the admission day itself subjected to availability..