**Core Concept**
Iron poisoning is a life-threatening condition where excess iron accumulates in the body, causing oxidative damage and organ failure. Treatment focuses on removing iron from the body, primarily through chelation therapy, and supportive measures like gastric decontamination.

**Why the Correct Answer is Right**
Desferrioxamine (B) is a specific iron chelator used in severe iron poisoning to bind and remove iron from the bloodstream. Gastric lavage (C) is used in early stages to remove unabsorbed iron from the stomach. Magnesium hydroxide (A) acts as an antacid and may be used in some cases to neutralize gastric acid, though it is not a primary antidote. Penicillamine (D), while used in copper poisoning, is **not effective** in iron poisoning and is not recommended due to poor iron binding and increased risk of adverse effects.

**Why Each Wrong Option is Incorrect**
Option A: Magnesium hydroxide is used in iron poisoning as an antacid to reduce gastric acidity, aiding in iron absorption inhibition, though it is not a primary antidote.
Option B: Desferrioxamine is a gold-standard chelator for iron poisoning, especially in severe cases.
Option C: Gastric lavage is used in early stages to remove iron from the stomach before absorption.

**Clinical Pearl / High-Yield Fact**
Penicillamine is **not** used in iron poisoning — it is only effective in **copper** poisoning. Always remember: "Iron → Desferrioxamine; Copper → Penicillamine."

✓ Correct Answer: D. Penicillamine