**Core Concept**
The patient's symptoms and test results suggest a conductive or sensorineural hearing loss. Conductive hearing loss occurs when there's a problem with the middle ear, while sensorineural hearing loss is related to the inner ear or the auditory nerve. Rinne's test compares air conduction to bone conduction, while Weber's test assesses lateralization of sound.

**Why the Correct Answer is Right**
The patient's negative Rinne's test result on the right side indicates that bone conduction is better than air conduction, which is characteristic of sensorineural hearing loss. The lateralization to the left side on Weber's test suggests that the right ear is not functioning properly, leading to the brain relying more on the left ear for sound localization. This points towards a unilateral sensorineural hearing loss on the right side.

**Why Each Wrong Option is Incorrect**
**Option A:** Conductive hearing loss typically has a positive Rinne's test result, as air conduction is better than bone conduction. This option doesn't match the patient's test results.
**Option B:** Binaural hearing loss would likely result in bilateral involvement, not unilateral as seen in this case.
**Option C:** Mixed hearing loss combines conductive and sensorineural components, but the patient's test results are more indicative of a pure sensorineural loss.

**Clinical Pearl / High-Yield Fact**
Remember that a negative Rinne's test result with lateralization to the other ear on Weber's test suggests a sensorineural hearing loss, which often requires a more thorough audiological evaluation and potential referral to an otolaryngologist or audiologist.

**Correct Answer: A. Sensorineural hearing loss.**