This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Superior pa of IVC develops from which pa? \nSelect and explain. \nA. Right vitelline vein, B. Subcardinal vein, C. Anterior cardinal vein, D. Sacrocardinal vein', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Anterior cardinal vein and subcardinal vein will be degenerated during development where as sacrocardinal segment forms the inferior pa. Reference: TEXTBOOK OF CLINICAL EMBRYOLOGY.... VISHRAM SINGH SECOND EDITION....PAGE NO:245', 'role': 'assistant'}]