**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. This occurs due to mutations in the ATP7B gene, which is responsible for regulating copper transport and metabolism.

**Why the Correct Answer is Right**
Copper deposition in Wilson's disease primarily involves the accumulation of copper in the lysosomes of hepatocytes, leading to cellular damage and dysfunction. The ATP7B protein plays a crucial role in transporting copper out of the liver and into bile, where it can be excreted. In Wilson's disease, the defective ATP7B protein results in copper accumulation in the liver, leading to liver damage and other systemic complications.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as Wilson's disease primarily affects the liver and brain, not the kidneys.
**Option B:** This option is incorrect as copper deposition in Wilson's disease is not primarily associated with the pancreas.
**Option C:** This option is incorrect as Wilson's disease is a genetic disorder, not a result of environmental exposure to copper.

**Clinical Pearl / High-Yield Fact**
Wilson's disease is an important consideration in patients presenting with acute liver failure, particularly in young individuals without a history of alcohol use or viral hepatitis.

**Correct Answer: C. Brain and liver**