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: Anatomy
[{'content': 'Umbilical vesicle attains full development in? \nSelect and explain. \nA. 2 week, B. 4 week, C. 6 week, D. 7 week', 'role': 'user'}, {'content': 'Answer: B \nExplanation: B i.e. 4 week', 'role': 'assistant'}]