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': 'The method of prepayment wherein the patient pays a percent of total cost: \nSelect and explain. \nA. Loan, B. Co-insurance, C. Reasonable fee, D. Fee for service', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]