**Core Concept**
VIPomas are rare neuroendocrine tumors that secrete vasoactive intestinal peptide (VIP), leading to a clinical syndrome characterized by excessive gastrointestinal fluid secretion, hypokalemia, and diarrhea. The pathophysiology involves the stimulation of VIP receptors in the gut, leading to increased chloride and bicarbonate secretion.

**Why the Correct Answer is Right**
VIPomas are known for causing symptoms such as:
- Severe watery diarrhea, often leading to dehydration and electrolyte imbalances
- Hypokalemia due to potassium loss in the stool
- Weight loss and malnutrition secondary to chronic diarrhea
- Hypochloremic metabolic alkalosis due to excessive chloride loss

**Why Each Wrong Option is Incorrect**
**Option A:** This option may be a symptom of a VIPoma, as the excessive gastrointestinal fluid secretion can lead to hypovolemia and subsequent hypotension.
**Option B:** Hypokalemia is a common symptom of VIPomas, resulting from potassium loss in the stool.
**Option C:** Diarrhea is a hallmark symptom of VIPomas, making this option incorrect.

**Clinical Pearl / High-Yield Fact**
VIPomas are often associated with other neuroendocrine tumors, such as pancreatic islet cell carcinomas, and can be diagnosed using a 24-hour urinary VIP level measurement.

**Correct Answer: C. Diarrhea is a hallmark symptom of VIPomas.**