**Core Concept**
D-penicillamine is a chelating agent used in the treatment of Wilson's disease, rheumatoid arthritis, and other conditions involving heavy metal toxicity or autoimmune disorders. It works by forming a stable complex with copper, mercury, and other metals, facilitating their excretion from the body.

**Why the Correct Answer is Right**
The correct answer involves an understanding of the pharmacological mechanism of D-penicillamine. **D-penicillamine** forms a stable complex with copper ions, which are then excreted in the urine. This leads to a decrease in copper levels within the body, especially in the liver and brain, thereby alleviating symptoms associated with copper toxicity.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the context of D-penicillamine overexposure.
**Option B:** D-penicillamine does not work by inhibiting the enzyme responsible for copper absorption.
**Option C:** While D-penicillamine is used to treat Wilson's disease, overexposure to it does not lead to an increase in copper levels in the body.

**Clinical Pearl / High-Yield Fact**
D-penicillamine can cause a range of side effects, including proteinuria, thrombocytopenia, and Goodpasture syndrome, due to its ability to bind to various proteins and induce an immune response.

**Correct Answer: D. Copper levels in the body decrease.**