## **Core Concept**
The question tests the understanding of specific hearing loss patterns and their associations with various conditions. Selective low-frequency sensorineural hearing loss refers to a particular audiometric pattern where there is a more significant decline in hearing thresholds at lower frequencies compared to higher frequencies. This pattern can be seen in specific conditions.

## **Why the Correct Answer is Right**
The correct answer, **C. Mumps**, is associated with selective low-frequency sensorineural hearing loss. Mumps, caused by the mumps virus, can lead to inner ear involvement, specifically affecting the cochlea. This results in a characteristic low-frequency sensorineural hearing loss. The mechanism likely involves viral infection of the inner ear structures.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Not specified, but generally, other viral infections might cause hearing loss, but the specific pattern and association need to match.
- **Option B:** Not specified, but conditions like otosclerosis typically cause conductive hearing loss or a different pattern of sensorineural hearing loss.
- **Option D:** Not specified, but other conditions might cause hearing loss through different mechanisms or have different audiometric patterns.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **mumps** can cause unilateral low-frequency sensorineural hearing loss. This condition highlights the importance of considering viral infections in the differential diagnosis of sudden sensorineural hearing loss, particularly with a low-frequency pattern.

## **Correct Answer:** . Mumps