Ascent to altitude or descent from altitude is often accom panied by periods of reduced hearing
sensitivity, crackling sounds and return to norm al sensitivity. This is due to

A) Swelling of the cochlear fluid with reduced external pressure
B) Movement of the oval window as the cochlea unwinds
C) Bulging of the round window with reduced external pressure
D) Movement of the tympanic membrane with unequal pressure between the middle ear
and outer ear
E) Different states of contractions of the stapedius muscle and tensor tympani