**Core Concept**
Pancreatitis, an inflammatory condition of the pancreas, can be acute or chronic. The most common cause of pancreatitis is gallstones, which block the bile duct and obstruct the flow of pancreatic juice, leading to inflammation.

**Why the Correct Answer is Right**
Gallstones, typically cholesterol stones, lodge in the ampulla of Vater and obstruct the pancreatic duct, causing pancreatic juice to flow back into the pancreas and trigger inflammation. This mechanism is known as biliary pancreatitis. The obstruction leads to enzymatic autodigestion of the pancreas, resulting in necrosis and inflammation.

**Why Each Wrong Option is Incorrect**
**Option A:** Alcohol-induced pancreatitis is a common cause, but it accounts for a smaller percentage of cases compared to gallstone-induced pancreatitis.
**Option B:** Idiopathic pancreatitis, where no cause is identified, is a diagnosis of exclusion and occurs in a small percentage of cases.
**Option C:** Hypertriglyceridemia-induced pancreatitis is a rare cause, typically seen in patients with very high triglyceride levels.

**Clinical Pearl / High-Yield Fact**
The modified Glasgow criteria can be used to predict the severity of acute pancreatitis, with a score of 3 or more indicating severe disease.

**Correct Answer:** C. Gallstones