This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anatomy of Middle Ear, Subject name: ENT
Politzer bag maneuver used to test: 
Select and explain. 
A. Eustachian tube, B. Larynx, C. Esophagus, D. Nasal cavity
A: Eustachian tube
Answer: A: Eustachian tube 
Explanation: Politzer bag maneuver used to test Eustachian tube Designed for those who can`t perform Valsalva test Politzer bag is connected to rubber tube- Tube is placed in one nostril and other is closed-Air is blown with pressure by pressing the bulb-Air enters nasopharynx - opens eustachian tube & enters middle ear- pops out TM