This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: ENT
Cottel's test is used for - 
Select and explain. 
A. Septal perforation, B. Rhinophyma, C. Choanal atresia, D. DNS
D: DNS
Answer: D: DNS 
Explanation: Ans. is cd' i.e., DNS o Cottle test: It is used to test nasal obstruction due to abnormality of nasal valve as in case of deviated nasal septum. o In this test, cheek is drawn laterally while the patient breathes quietly. If the nasal airway improves on the test side, the test is positive, and indicates abnormality of the vestibular component of nasal valve.