**Core Concept**
The patient's conductive deafness is likely due to a problem with the middle ear, which affects sound conduction to the inner ear. This could be related to a disruption in the normal functioning of the ossicles or middle ear structures.

**Why the Correct Answer is Right**
The patient's normal and mobile tympanic membrane suggests that the issue is not with the tympanic membrane itself, but rather with the middle ear structures. The most likely cause of conductive deafness in this scenario is a fracture of the ossicles, specifically the malleus or incus. This would disrupt the normal conduction of sound through the middle ear. The fracture could be due to the head injury, causing damage to the ossicles.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.
**Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that conductive deafness can be caused by various factors, including middle ear infections, otosclerosis, or trauma. However, in the context of head injury, a fracture of the ossicles is a critical consideration.

**Correct Answer: C. Perforation of the tympanic membrane is not seen in conductive deafness with a normal tympanic membrane.**