A person is exercising, burning 850 Cal/hr. While doing this exercise, they breathe deeply, so the volume they take into and out of their lungs is 2 L with each breath. 20% of the air inhaled is oxygen, and 16% of the air exhaled is oxygen. How fast do they have to breath? Answer will be exact.

a)    15.1 Breaths/min

b)   11.7 Breaths/min

c)    22.0 Breaths/min

d)   36.7 Breaths/min

e)    53.0 Breaths/min