**Core Concept**
VIPoma is a rare neuroendocrine tumor of the pancreas that secretes vasoactive intestinal peptide (VIP), leading to watery diarrhea, hypotension, and electrolyte imbalances due to profound secretion of chloride and water in the intestines.

**Why the Correct Answer is Right**
VIPomas cause **watery diarrhea** due to activation of chloride and water secretion in the small intestine via the **cAMP pathway**. This results in **severe hypotension** due to vasodilation and reduced vascular resistance. The clinical triad of **persistent diarrhea, hypotension, and dehydration** is classic for VIPoma. It is a paraneoplastic syndrome, and diagnosis is confirmed by elevated serum VIP levels.

**Why Each Wrong Option is Incorrect**
Option B: ACTHoma causes Cushing’s syndrome (hyperpigmentation, hypertension, muscle wasting), not diarrhea or hypotension.
Option C: GRFoma leads to hyperglycemia and hypertension via growth hormone release, not diarrhea.
Option D: Glucagnoma causes hyperglycemia, weight loss, and insulin resistance, with no diarrhea or hypotension.

**Clinical Pearl / High-Yield Fact**
Remember the mnemonic **"VIP = Vomiting, Inability to absorb, Profuse diarrhea"** — but in reality, VIPoma presents with **watery diarrhea and hypotension**, not vomiting. Always consider VIPoma in patients with **chronic diarrhea and low blood pressure**.

✓ Correct Answer: A. VIPoma