## **Core Concept**
The question tests the knowledge of ototoxicity associated with anti-tubercular drugs. Ototoxicity refers to the property of being toxic to the ear (oto-), specifically the cochlea or vestibular structures, causing hearing or balance problems. Certain antibiotics, including some used in the treatment of tuberculosis, are known to have this side effect.

## **Why the Correct Answer is Right**
The correct answer, , is associated with ototoxicity. The drug in question is likely **Streptomycin**, an aminoglycoside antibiotic used in the treatment of tuberculosis. Streptomycin is well-known for its potential to cause ototoxicity, leading to vestibular damage (affecting balance) and sometimes cochlear damage (affecting hearing), which can manifest as deafness and tinnitus. This is due to its mechanism of action that can interfere with the function of the hair cells in the inner ear.

## **Why Each Wrong Option is Incorrect**
- **Option A:** is not commonly associated with ototoxicity to the extent of causing deafness and tinnitus as a primary side effect.
- **Option B:** is another anti-tubercular drug but is not primarily known for ototoxicity compared to aminoglycosides like streptomycin.
- **Option D:** is not typically associated with significant ototoxicity.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that aminoglycoside antibiotics, such as **streptomycin**, are a common cause of ototoxicity. Monitoring for hearing loss and vestibular dysfunction is crucial when using these medications. The use of streptomycin has declined due to its side effects, but it remains an option for certain cases of tuberculosis.

## **Correct Answer:** . Streptomycin