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': 'Pulp chamber is absent in: \nSelect and explain. \nA. Dentinogenesis imperfecta, B. Amelogenesis imperfecta, C. Craniofacial dysostosis, D. None of the above', 'role': 'user'}, {'content': "Answer: A \nExplanation: Dentinogenesis imperfecta is an autosomal dominant condition affecting both deciduous and permanent teeth. Affected teeth are gray to yellowish-brown and have broad crowns with constriction of the cervical area resulting in a ‘tulip’ shape. Radiographically, the teeth appear solid, lacking pulp chambers and root canals. Enamel is easily broken leading to exposure of dentin that undergoes accelerated attrition.\nRef: Shafer's textbook of oral pathology 7th edition page 55", 'role': 'assistant'}]