**Core Concept**
Acute pancreatitis is a sudden inflammation of the pancreas that can be caused by various factors, including gallstones, alcohol abuse, and hypertriglyceridemia. The condition can lead to pancreatic enzyme activation, tissue damage, and potentially life-threatening complications.

**Why the Correct Answer is Right**
Acute pancreatitis is commonly caused by gallstones, which can obstruct the pancreatic duct and lead to pancreatic enzyme activation. Alcohol abuse is another well-known cause, as it can cause chronic pancreatitis and increase the risk of acute pancreatitis. Hypertriglyceridemia is also a recognized cause, particularly in patients with severe hypertriglyceridemia, as it can lead to the formation of triglyceride-rich lipids that can cause pancreatitis. The pancreas is sensitive to high levels of triglycerides, which can trigger an inflammatory response and tissue damage.

**Why Each Wrong Option is Incorrect**
**Option B:** Starvation is not a recognized cause of acute pancreatitis. While malnutrition can exacerbate pancreatitis, starvation itself is not a direct cause of the condition.
**Option C:** Hypercalcemia can contribute to the development of acute pancreatitis, but it is not a primary cause. Elevated calcium levels can stimulate pancreatic enzyme secretion and exacerbate pancreatitis.
**Option D:** Hypercalcemia is not a recognized cause of acute pancreatitis. While hypercalcemia can contribute to pancreatitis, it is not a primary cause of the condition.

**Clinical Pearl / High-Yield Fact**
Remember that hypertriglyceridemia is a well-recognized cause of acute pancreatitis, particularly in patients with severe hypertriglyceridemia. This is a critical piece of information for patients who present with acute pancreatitis and have a history of hypertriglyceridemia.

**Correct Answer: A. Gallstones**