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': 'Double Blind Study, true is ? \nSelect and explain. \nA. The research investigator is blind to the dependent & independent variable, B. The subject in the study do not know the examiner doing the study, C. The subject & the examiner do not know the details of the study, D. Only the examiner know the group to which subject belongs', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]