**Core Concept**
The question is testing the knowledge of investigations that can lead to acute pancreatitis, a condition characterized by inflammation of the pancreas. This can be caused by various factors, including gallstones, alcohol abuse, and certain medical procedures.

**Why the Correct Answer is Right**
One such investigation that can lead to acute pancreatitis is **ERCP (Endoscopic Retrograde Cholangiopancreatography)**. ERCP is a medical procedure used to diagnose and treat problems in the bile and pancreatic ducts. During the procedure, a catheter is inserted through the mouth and guided through the stomach and duodenum to reach the bile and pancreatic ducts. However, the procedure can cause pancreatitis due to the manipulation of the pancreatic duct and the injection of contrast dye. The risk of pancreatitis is higher if the pancreatic duct is manipulated, and the procedure is often performed in patients with a history of pancreatitis or sphincter of Oddi dysfunction.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not specified, but other common investigations like CT scans, MRI, or ultrasound do not typically cause pancreatitis.
* **Option B:** This option is also not specified, but other investigations like endoscopy or colonoscopy are not commonly associated with pancreatitis.
* **Option C:** This option is not specified, but certain medications like steroids or some antibiotics can cause pancreatitis as a side effect, but this is not the context of an investigation leading to pancreatitis.

**Clinical Pearl / High-Yield Fact**
It's essential to note that ERCP is a high-risk procedure for pancreatitis, and patients should be carefully selected and prepared before undergoing the procedure. A history of pancreatitis or sphincter of Oddi dysfunction should be a contraindication for ERCP unless absolutely necessary.

**Correct Answer: C. ERCP**