The correct answer is B.  

The rescuer here does not have an AED.  This is basic CPR approach.  This reminds the learner of the core steps of CPR: verify unresponsiveness, call 911, get the AED.  

Answer a is wrong because giving 2 breaths and 15 compressions comes later in the sequence, not first.  

Answer c is wrong because the pocket facemask is in the AED carrying case usually, and rescue breathing is later in the sequence.  

Answer d is wrong because there is no indication for the Heimlich maneuver and because that action would occur later in the sequence.