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: Pathology
[{'content': 'The defect in Berry aneurysm lies in: \nSelect and explain. \nA. Degeneration of internal elastic lamina, B. Degeneration of media / muscle cell layer of aery, C. Deposition of mucoid material in media, D. Low grade inflammation of vessel wall', 'role': 'user'}, {'content': 'Answer: B \nExplanation: . Degeneration of media / muscle cell layer of aery', 'role': 'assistant'}]