This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
[{'content': 'Cardiac septum develops by \nSelect and explain. \nA. 5-8 weeks, B. 9-12 weeks, C. 12-16 weeks, D. 16-18 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Cardiac septum developed by 5-8 weeks . Ref - sciencedirect.com', 'role': 'assistant'}]