The answer is...
B. Buffers
The answer would be B. Only during periods of stress. When you are stressed out you are most likely having a hard time relaxing. If you take deep breaths your breathing should slow down and your body will relax. D. Only when you've gotten enough sleep, has nothing to do with breathing, you don't need to take deep breaths after sleeping. C. No more than twice a day and A. Everyday, are both unnecessary, you don't need to take deep breaths everyday for no reason. Stress is the main reason people hyperventilate. They get stressed and they have varied symptoms. They can't breathe, have short amount of patience, etc. <span />
