A 20-year-old man presents with repeated episodes of haematemesis. There is no history of jaundice or liver decompensation. On examination, the significant findings include moderate splenomegaly and presence of oesophagal varices. There is no ascites or peptic ulceration. The liver function tests are normal. What is the most likely diagnosis
Extrahepatic poal venous obstruction Non-cirrhotic poal fibrosis Cirrhosis Hepatic venous outflow tract obstruction