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': 'Fracture or separation of porcelain and metal occurs due to: \nSelect and explain. \nA. Increased thickness of porcelain, B. High occlusal contact, C. No metal conditioner used, D. Centric occlusal contact on metal-ceramic interface', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]