## **Core Concept**
The question tests knowledge of pharmacology, specifically focusing on the chemical structure of certain drugs. Sulfhydryl groups (-SH) are functional groups that contain a sulfur-hydrogen bond. This question requires identification of a drug with two sulfhydryl groups in its molecular structure.

## **Why the Correct Answer is Right**
The correct answer, **Penicillamine**, is a drug that contains two sulfhydryl groups (-SH) in its molecule. Penicillamine is used in the treatment of Wilson's disease (a condition of excessive copper accumulation), cystinuria (a condition leading to kidney stones), and sometimes in rheumatoid arthritis. Its two sulfhydryl groups allow it to chelate metals and facilitate the excretion of heavy metals like copper.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option does not correspond to a commonly recognized drug with two sulfhydryl groups.
- **Option B:** Similarly, this option does not match a well-known drug with the specified chemical feature.
- **Option C:** This is not identified as a drug with two sulfhydryl groups.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that **Penicillamine** is specifically used for its chelating properties, particularly in Wilson's disease. Its effectiveness is closely related to its chemical structure, which includes two sulfhydryl groups.

## **Correct Answer:** . Penicillamine