This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
The most common cause of laryngeal stridor in a 60 year old male is - 
Select and explain. 
A. Nasopharyngeal carcinoma, B. Thyroid carcinoma, C. Foreign body aspiration, D. Carcinoma larynx
D: Carcinoma larynx
Answer: D: Carcinoma larynx 
Explanation: Most common cause for stridor in 60 years old male will be carcinoma larynx as carcinoma larynx occurs in males (predominantly) at the age of 40–70 years.
Most common and earliest symptom of subglottic cancer is stridor.
NOTE:

Nasopharyngeal cancer does not lead to stridor
Thyroid cancer causes stridor rarely
Foreign body aspiration is a common cause of stridor in children and not adults.