B is the correct sequence of events in an emergency situation.
It is important to check first, this is so you know for sure that the emergency is valid. If you were to call first, you could be misinformed. If you were to care first, you wouldn't even assess the type of situation and could make it worse.
B.) assess the situation so you can report it, report the situation by calling emergency responders, and give first aid if you are qualified and know what to do, if not keep the person calm if they are coherent.
