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': 'All ceramic crowns are not indicated for young children because of: \nSelect and explain. \nA. Short clinical crown height, B. Root formation is not completed, C. Pulp horns are wide and high, D. Maintenance of oral hygiene is difficult', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]