**Core Concept**
The patient's symptoms and test results suggest a conductive hearing loss in the right ear, which is confirmed by a negative Rinne's test and perceived tone louder in the left ear on Weber's test. Conductive hearing loss occurs when sound is not conducted through the middle ear to the inner ear due to a problem with the middle ear structures, such as the eardrum or ossicles.

**Why the Correct Answer is Right**
The patient's symptoms and test results are consistent with a conductive hearing loss. In a conductive hearing loss, the Rinne's test is negative because bone conduction is better than air conduction, and the Weber's test lateralizes to the better-hearing ear (in this case, the left ear). The patient's symptoms of decreased hearing in the right ear for the last 2 years, along with the test results, suggest a chronic conductive hearing loss.

**Option A:** Otosclerosis is a type of conductive hearing loss, but it typically presents with a positive Rinne's test and the Weber's test lateralizes to the affected ear.
**Option B:** Sensorineural hearing loss would present with a negative Rinne's test on both ears and the Weber's test lateralizing to the affected ear.
**Option C:** Mixed hearing loss would present with a combination of conductive and sensorineural hearing loss, which is not consistent with the patient's test results.

**Clinical Pearl / High-Yield Fact**
In patients with conductive hearing loss, the Rinne's test is typically negative, and the Weber's test lateralizes to the better-hearing ear. Otosclerosis is a common cause of conductive hearing loss in young adults.

**Correct Answer:** C. Mixed hearing loss would present with a combination of conductive and sensorineural hearing loss, which is not consistent with the patient's test results