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': 'Composites are not recommended for direct posterior restorations in all the following except: \nSelect and explain. \nA. Heavy occlusal stresses, B. Deep subgingival areas, C. Interim restorations, D. Isolation is not possible', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]