This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pharynx, larynx and trachea and cranial nerves 3,4,6, Subject name: Anatomy
[{'content': 'All are true regarding trachea EXCEPT? \nSelect and explain. \nA. Has C shaped cailages, B. Outer diameter is 2 cm, C. More than 20 hyaline cailages, D. Isthmus of thyroid gland lies at 2, 3 and 4th tracheal rings', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Trachea Length - 10- 15cm Diameter - 2cm (males), 1.5cm (females) Upper end - at lower end of cricoid cailage. Lower end - sternal angle C6 - T6 (erect position in living person). Fibroelastic wall. Cailaginous skeleton suppoed by 16 - 20 C- Shaped rings. Lumen lined by ciliated pseudostratified columnar epithelium', 'role': 'assistant'}]