What two gases are present in the lungs at 50,000 feet, and what are their lung pressures?

A) Oxygen - 20 mmHg, Nitrogen - 80 mmHg
B) Oxygen - 0 mmHg, Nitrogen - 100 mmHg
C) Oxygen - 10 mmHg, Nitrogen - 90 mmHg
D) Oxygen - 5 mmHg, Nitrogen - 95 mmHg