Final answer:
The C-rings of hyaline cartilage in the trachea function to provide structural support to keep the airway open for breathing.
Step-by-step explanation:
The function of the C-rings of hyaline cartilage in the trachea is to provide structural support to keep the airway patent or open for breathing. The trachea is made of incomplete rings of hyaline cartilage, which provide strength and support to prevent the trachea from collapsing. This structural support ensures that the trachea remains open and allows for the passage of air.