**Core Concept**
Arsenic is a toxic metalloid that affects multiple organ systems, primarily through its oxidative stress and genotoxic properties. It can cause a range of clinical manifestations, from acute poisoning to chronic exposure-related diseases.

**Why the Correct Answer is Right**
Arsenic exposure is known to cause skin lesions, particularly hyperpigmentation and hyperkeratosis, which are manifestations of its toxic effects on the skin. The exact mechanism involves the generation of reactive oxygen species (ROS) that damage skin cells, leading to the characteristic lesions. Additionally, arsenic exposure is associated with an increased risk of skin cancers, particularly basal cell carcinoma and squamous cell carcinoma.

**Why Each Wrong Option is Incorrect**
**Option A:** Arsenic is not primarily associated with causing cardiac arrhythmias.
**Option B:** While arsenic exposure is linked to various cancers, it is not specifically known for causing lung cancer.
**Option C:** Arsenic is not typically associated with causing neurodegenerative diseases like Alzheimer's or Parkinson's.

**Clinical Pearl / High-Yield Fact**
Arsenic exposure can also cause peripheral neuropathy, which is characterized by numbness, tingling, and muscle weakness in the hands and feet.

**Correct Answer: D**. Skin lesions.