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: Dental
[{'content': 'The marrow found in the mandible is: \nSelect and explain. \nA. All fatty marrow, B. All red marrow, C. All fibrous marrow, D. A combination of fatty and fibrous marrow', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]