This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
[{'content': 'Inferior mesenteric vein drains into vein- \nSelect and explain. \nA. Splenic, B. Hepatic, C. Portal, D. Inf. vena cava', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Splenic', 'role': 'assistant'}]