As you travel up a mountain in your car, you notice that your hearing diminishes. You realize that your ears are stopping up, and you swallow several time to clear them. Why does this happen? A) your tympanic membrane gets washed off by your saliva. B) swallowing equalizes the pressure between your pharynx and middle ear via the Eustachian tube. C) fluid builds up as you increase altitude, and when you swallow, you swallow the fluid.. D) swallowing makes the tympanic membrane move in and out.