Final answer:
The trachea, a structure of the human respiratory system, is supported by approximately 16-20 C-shaped cartilaginous rings, ensuring the airways remain open.
Step-by-step explanation:
The question does not specify the context in which 'C' shaped rings are used. If the context is the human anatomy, specifically the respiratory system, then the answer would be related to the structure of the trachea (windpipe). The trachea is supported by approximately 16-20 C-shaped cartilaginous rings which maintain open airways so that air can pass into the lungs. If this is in relation to another subject or context, additional information would be required to accurately answer the question. It is always pivotal to understand the context when answering questions to ensure accuracy.