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': 'A dens in dente is usually caused by: \nSelect and explain. \nA. An abnormal proliferation of pulp tissue, B. Denticle formation within the pulp tissue, C. A deep invagination of the enamel organ during formation, D. A supernumerary tooth bud enclaved within a normal tooth.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]