Yes, B2 is air ventilated but it's actually still cold cos you can feel the aircon from B1 which is just next to B2.
B1 is private so remember you'll be charged as a private patient and all your appointments including your baby's stay will be considered as private patient.
C ward is more open, no walls so basically you get to see everyone else. But again, it's Covid period. Only 1 visitor is allowed to the wards so you'll still get your privacy (curtains off will do, same for B2).