This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neck, Subject name: Surgery
In performing a tracheostomy, authorities agree that 
Select and explain. 
A. The strap muscles should be divided, B. The thyroid isthmus should be preserved, C. The trachea should be entered at the second or third cartilaginous ring, D. Only horizontal incisions should be used
C: The trachea should be entered at the second or third cartilaginous ring
Answer: C: The trachea should be entered at the second or third cartilaginous ring 
Explanation: Although tracheostomy is occasionally an emergency procedure, it can be more effectively performed in an operating room where hemostasis and antisepsis are readily achieved. Most authorities recommend a horizontal incision; however, limited direct midline incisions have the advantage of not opening any unnecessary tissue planes and perhaps reducing the incidence of bleeding complications. Both approaches have advocates. In either case, the skin incision is made just below the cricoid cartilage, the strap muscles are spared and retracted, the thyroid isthmus is divided if necessary, and the trachea is entered at the second tracheal ring. The second and third tracheal rings are incised vertically, allowing placement of the tracheostomy tube. The first tracheal ring and the cricoid cartilage must be left intact.