Which of the following best describes what happens when the lungs expand?

A) Contraction of the muscles of inspiration pushes the diaphragm up, causing air to flow into the lungs.
B) Contraction of the muscles of inspiration decreases the volume of the thorax, causing a decrease in pressure (Boyle's law).
C) Expansion of the thorax causes the lungs to expand as a function of the negative intrapleural pressure between the parietal and visceral pleurae.
D) None of the above.