**Core Concept**
Non-cirrhotic portal fibrosis (NCPF) is a rare cause of portal hypertension characterized by the deposition of fibrous tissue in the portal tracts without significant liver damage or cirrhosis. This condition leads to increased resistance to blood flow in the portal vein, resulting in portal hypertension and its complications, including the formation of esophageal varices.

**Why the Correct Answer is Right**
The presence of esophageal varices, splenomegaly, and normal liver function tests in the absence of jaundice or liver decompensation suggests portal hypertension without significant liver damage. Non-cirrhotic portal fibrosis is a well-known cause of portal hypertension, and the absence of cirrhosis or other liver damage makes options C and D less likely. The deposition of fibrous tissue in the portal tracts in NCPF leads to increased resistance to blood flow, resulting in portal hypertension and its complications.

**Why Each Wrong Option is Incorrect**
**Option A:** Extra hepatic portal venous obstruction is a cause of portal hypertension, but it typically presents in childhood, and the liver function tests are usually normal. The presence of esophageal varices and splenomegaly in this patient suggests a more chronic process, making option A less likely.

**Option C:** Cirrhosis is a common cause of portal hypertension, but the liver function tests are normal in this patient, making cirrhosis less likely. Additionally, cirrhosis is typically characterized by liver damage and fibrosis, which is not present in this patient.

**Option D:** Hepatic venous outflow tract obstruction is a rare cause of portal hypertension, but it typically presents with signs of liver dysfunction, such as ascites and jaundice, which are not present in this patient.

**Clinical Pearl / High-Yield Fact**
Non-cirrhotic portal fibrosis is a rare cause of portal hypertension that should be considered in patients with esophageal varices and splenomegaly in the absence of cirrhosis or other liver damage.

**✓ Correct Answer: B. Non-cirrhotic portal fibrosis**