This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skeletal System, Subject name: Radiology
[{'content': "Marble bone is characteristic of? \nSelect and explain. \nA. Osteopetrosis, B. Marfan's syndrome, C. Osteogenesis imperfecta, D. Melorheostosis", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans AOsteopetrosis, also known as Marble bone disease, or Albers- Schonberg disease is an extremely rare inherited disorder whereby the bones harden, becoming denser due to defect in osteoclastic bone resorption.', 'role': 'assistant'}]