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': 'A stipulated flat sum the patient has to pay towards the cost of service before it goes into: \nSelect and explain. \nA. Ground insurance, B. Co-insurance, C. Co-payment, D. Deductible', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]