Choice A rationale:

Redness of the tympanic membrane can indicate inflammation, which is a common sign of acute otitis media (AOM).

Inflammation causes increased blood flow to the area, leading to redness and often pain.

Choice B rationale:

Bulging of the tympanic membrane occurs when there is increased pressure behind the eardrum, often due to fluid accumulation.

In the context of acute otitis media, this bulging is caused by the buildup of pus or other fluids in the middle ear.

Choice C rationale:

Purulence (pus) observed in the ear canal is a definitive sign of acute otitis media.

The presence of pus indicates an active infection within the middle ear.

Choice D rationale:

Orange discoloration of the tympanic membrane is not a typical finding in acute otitis media.

The color change could be due to various factors but is not specific to this condition.

Choice E rationale:

Decreased mobility of the tympanic membrane can occur due to the accumulation of fluid in the middle ear, leading to impaired movement.

This decreased mobility is often observed in acute otitis media and contributes to the diagnosis.