**Core Concept:**
The question is testing the clinical presentation and differential diagnosis of a patient with sudden onset epigastric pain radiating to the back in the context of a chronic alcoholic patient. The question specifically mentions a patient with a history of chronic alcohol consumption, which increases the likelihood of diagnosing alcoholic pancreatitis or alcoholic hepatitis.

**Why the Correct Answer is Right:**
The correct answer is **D.** Acute cholecystitis, also known as acute gallstone pancreatitis, does not involve epigastric pain radiating to the back, which is a characteristic feature of the described clinical presentation. Acute cholecystitis typically presents with pain in the right hypochondrium, which is the upper right quadrant of the abdomen and is not related to epigastric pain radiating to the back. Acute pancreatitis presents with the mentioned symptoms, making option D the correct choice.

**Why Each Wrong Option is Incorrect:**

A. **Acute appendicitis:** This condition presents with pain in the right lower quadrant of the abdomen, not epigastric pain radiating to the back. Acute appendicitis is an unrelated differential diagnosis in this context.

B. **Acute myocardial infarction (heart attack):** This diagnosis is characterized by chest pain, not epigastric pain radiating to the back. The clinical presentation does not match the described symptoms.

C. **Acute pancreatitis:** Though this option is correct, it is not the correct answer as it involves epigastric pain radiating to the back, the very symptom the patient is presenting with.

**Clinical Pearl:**
A history of chronic alcohol consumption in a patient presenting with acute abdominal pain and back pain is highly suggestive of acute pancreatitis. However, the correct answer should be distinguished from the other options based on the specific symptoms mentioned in the question.

**Why Each Wrong Option is Incorrect:**
A. **Acute appendicitis:** This condition presents with pain in the right lower quadrant of the abdomen, not epigastric pain radiating to the back. The clinical presentation does not match the described symptoms.

B. **Acute myocardial infarction (heart attack):** This diagnosis is characterized by chest pain, not epigastric pain radiating to the back. The clinical presentation does not match the described symptoms.

C. **Acute pancreatitis:** Though this option is correct, it is not the correct answer as it involves epigastric pain radiating to the back, the very symptom the patient is presenting with.

**Correct Answer:**
D. **Acute cholecystitis (gallstone pancreatitis):** This condition presents with epigastric pain radiating to the back, which is consistent with the described symptoms. Acute cholecystitis is a differential diagnosis for acute pancreatitis.

**Clinical Pearl:**
A history of chronic alcohol consumption is a risk factor for both acute pancreatitis and acute cholecystitis, but the clinical presentation of the described symptoms should guide the differential diagnosis towards pancreatitis.

In summary, the correct answer is **D** (acute cholecystitis) because it