What Function Do the C-Shaped Tracheal Cartilages Allow

What function do the C-shaped tracheal cartilages allow?

A) Allow room for the trachea to expand if you inhale a large volume of air.
B) Allow room for the esophagus to expand during swallowing.
C) Allow room for blood pulses to expand the common carotid artery without interfering with air flow.
D) Allow the trachea to collapse on itself when no inhalation or exhalation is occurring to reduce space in the mediastinum.
E) Allow gas diffusion to occur around the cartilage surfaces and the tissues of the mediastinum.