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': 'Porcelain jacket crowns are contraindicated in \nSelect and explain. \nA. Hypoplastic teeth, B. Excessive horizontal overlap, C. Decay is extensive but pulp is vital, D. Excessive vertical overlap with little horizontal overlap', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]