**Core Concept**
Wilson disease is a genetic disorder characterized by excessive accumulation of copper in the body, particularly in the liver and brain. Zinc is used as a chelating agent to treat Wilson disease by enhancing the excretion of copper. The therapy works by forming a tight complex with copper, which is then excreted in the urine.

**Why the Correct Answer is Right**
Zinc therapy for Wilson disease has several advantages. It is a well-tolerated and effective treatment option, with minimal side effects. Zinc increases the intestinal excretion of copper by activating the metallothionein protein, which binds to copper and prevents its absorption in the gut. Additionally, zinc has a synergistic effect when used in combination with penicillamine, another chelating agent used to treat Wilson disease.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a known disadvantage of zinc therapy for Wilson disease. Zinc is generally well-tolerated and does not have significant side effects.
**Option B:** This option is incorrect because it is a known advantage of zinc therapy for Wilson disease, not a disadvantage. Zinc is effective in enhancing the excretion of copper.
**Option C:** This option is incorrect because it is not a known disadvantage of zinc therapy for Wilson disease. Zinc has a synergistic effect when used in combination with penicillamine.

**Clinical Pearl / High-Yield Fact**
Zinc therapy for Wilson disease is most effective when used in combination with penicillamine. This combination therapy can enhance the excretion of copper and improve treatment outcomes.

**Correct Answer: A.**