## **Core Concept**
Dimercaprol, also known as British Anti-Lewisite (BAL), is a chelating agent used in the treatment of heavy metal poisoning. It works by binding to the metal ions, forming a stable complex that can be excreted from the body.

## **Why the Correct Answer is Right**
Dimercaprol is specifically used for the treatment of poisoning with certain heavy metals. Among the options provided, it is effective in the treatment of poisoning with **arsenic (As)**, **mercury (Hg)**, and **lead (Pb)**. Dimercaprol forms a stable complex with these metals, facilitating their excretion and reducing their toxic effects.

## **Why Each Wrong Option is Incorrect**
* **Option D:** Acetaminophen poisoning is treated with N-acetylcysteine, not dimercaprol. N-acetylcysteine works by replenishing glutathione stores and directly binding to the toxic metabolite of acetaminophen.
* **Option E:** Iron poisoning is treated with deferoxamine, a specific chelator for iron. Dimercaprol is not used for iron poisoning.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that dimercaprol is used for heavy metal poisoning, particularly for **arsenic**, **mercury**, and **lead**. It is often used in combination with other chelating agents for certain types of poisoning.

## **Correct Answer:** . c) As, b) Hg, a) Pb.