While hiking in the mountains in Alaska, Pete encountered a giant grizzly bear. He immediately felt his heart rate increase, his breathing become rapid, and sweat drip down his back. These events were most likely due to effects of the neurotransmitter called .

Iwould say a is correct

20 times a minute is usually the average respritory rate of an adult. additionally the patient is breathing on his own, is clearly maintaining his airway, and is intaking a sufficient amount of air. you shouldn't use a bag valve mask, cpap, or other form of positive pressure ventilation, unless the patient has lost control of his airway, and is not breathing (apneic) or has rapid breathing or slow and shallow respirations. this patient would most likely and should be put on an non-rebreather mask or nrb attached to 100% high flow oxygen at 15 l/min. don't use a nasal cannula, as the amount of oxygen it provides is limited with a rate of 6 l/min.