Final answer:
Occlusion of the hepatic veins is typically caused by Budd-Chiari syndrome, a disorder that leads to an obstruction in the hepatic veins and results in liver enlargement and portal hypertension. Option a) is correct.
Step-by-step explanation:
Occlusion of the hepatic veins is most commonly a result of Budd-Chiari syndrome. Budd-Chiari syndrome is a rare liver disorder characterized by obstruction of the hepatic veins that drain blood from the liver. It leads to liver damage, as blood flow back to the heart is impeded, causing liver enlargement and portal hypertension. Since the hepatic portal system is a critical network of veins that provides blood to the liver from the gastrointestinal tract and spleen, its obstruction can have severe consequences.
In the context of liver blood flow, the hepatic artery supplies oxygenated blood, the hepatic portal vein delivers nutrient-rich but deoxygenated blood, and the hepatic vein drains the blood from the liver into the inferior vena cava.