Narrowest pa of airway is:
The subglottis is the narrowest poion of the airway in children, and the cricoid cailage is the only complete cailaginous ring in the airway. Because airflow in a cylinder is directly propoional to the fouh power of the radius, even a slight reduction in the area of the subglottis can lead to significant obstruction.
Subglottis
Carina
At vocal cords
None of the above