**Core Concept**
Sensorineural deafness, also known as sensorineural hearing loss, is a condition where there is damage to the inner ear or the auditory nerve. This type of hearing loss is often irreversible and can be caused by genetic factors, infections, or exposure to loud noises.

**Why the Correct Answer is Right**
In cases of severe sensorineural deafness, hearing aids may not be effective in improving hearing. This is because the damage is at the level of the inner ear or the auditory nerve, and hearing aids can only amplify sound, not repair the damaged structures. The next line of management would be to evaluate the child for cochlear implantation. Cochlear implants are medical devices that bypass damaged or non-functioning parts of the ear and directly stimulate the auditory nerve, allowing for the perception of sound.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the management of sensorineural deafness. Referral to an otolaryngologist is a general step in managing ear-related problems, but it does not address the specific issue of sensorineural hearing loss.
* **Option B:** This option is incorrect because it does not address the underlying cause of the hearing loss. While speech therapy may be beneficial for children with hearing impairments, it does not improve the underlying condition of sensorineural deafness.
* **Option C:** This option is incorrect because it is not a standard management strategy for sensorineural deafness. While some children may benefit from a bone-anchored hearing aid, this is not the next line of management for a child with severe sensorineural deafness.

**Clinical Pearl / High-Yield Fact**
Cochlear implants are a highly effective treatment for severe sensorineural deafness, particularly in children, and can significantly improve speech and language development.

**Correct Answer:** C. Cochlear implantation.