The right answer is Perform CPR.
What is wrong with proposal A is that it is not enough to call 911 and wait, you have to practice CPR in the meantime.
In case of cardiac arrest, there is not a minute to lose. When someone loses consciousness and no longer breathes, every second counts. The first thing to do is call civil defense or an ambulance. While waiting for help, the CPR is needed. A simple gesture that must be practiced without hesitation.