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': 'Three stages in progression of acute odontogenic infection are \nSelect and explain. \nA. Periapical osteitis, cellulitis, abscess, B. Abscess, cellulitis, periapical osteitis, C. Cellulitis, Abscess, periapical osteitis, D. Periapical osteitis, abscess, cellulitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]