**Core Concept**
Wilson's disease is a genetic disorder characterized by excessive accumulation of copper in the body, particularly in the liver, brain, and other organs. The management of Wilson's disease involves chelation therapy to remove excess copper from the body.

**Why the Correct Answer is Right**
Penicillamine is the drug of choice in pregnant women with Wilson's disease because it is a chelating agent that effectively removes copper from the body without causing significant harm to the fetus. Penicillamine works by forming a complex with copper ions, which are then excreted in the urine. This helps to reduce the levels of copper in the body and alleviate symptoms of the disease.

**Why Each Wrong Option is Incorrect**
**Option A:** Trientine is another chelating agent used to treat Wilson's disease, but it is not the preferred choice in pregnant women due to a higher risk of adverse effects.
**Option B:** Zinc acetate is used as a copper-chelating agent in Wilson's disease, but it is not suitable for pregnant women as it can displace zinc from essential proteins, leading to zinc deficiency.
**Option C:** Deferoxamine is a chelating agent used to treat iron overload, not copper overload, making it an incorrect choice for Wilson's disease.

**Clinical Pearl / High-Yield Fact**
In pregnant women with Wilson's disease, penicillamine is often initiated under close monitoring to minimize the risk of adverse effects on the fetus. Regular monitoring of liver function tests and copper levels is essential to ensure effective treatment.

**Correct Answer:** A. Penicillamine