Answer :
Answer:
Option A, The Eustachian tubes constrict
Explanation:
The Eustachian tubes basically equalizes the pressure in the middle ear whenever our ears are exposed to a varying outside pressure as compared to the pressure inside the ear. This happens very often with people who travel through flight or aqua divers, mountaineers etc. Thus, the role of Eustachian tubes is not very relevant when we are hearing something. It works even when we are not hearing anything.
Hence option A is correct.