A. No, any following traffic must stop if the door interferes with its progress
A. No, any following traffic must stop if the door interferes with its progress
B. Yes, you must not open a door if you are likely to cause danger to road users or impede traffic
C. No, there is no regulation to cover this situation
Some countries in Europe teach drivers to open their door with their opposite hand, ie. for us that would be our left hand. This means that you would have to turn your body to do it, and that means it will be easier to look over your shoulder.
Cyclists can be travelling at 40kph so they can approach quite quickly but might not be able to stop in time. It usually takes a cyclist further to stop than a car, even though they are lighter, because the amount of rubber in contact with the road is proportionally much less. If you open the door you run the risk of the cyclist swerving to avoid the door and instead hitting other traffic.
If you are a cyclist and you are riding next to parked cars, keep a look out for vehicles that look like they might open their door in front of you. Look for a driver's head movements, brake lights that go out, and the door opening a crack.
Opening your door into a cyclist in NSW attracts a fine of $298.
There's more information here about sharing the road with cyclists.