This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'In a double-blind clinical drug trial: \nSelect and explain. \nA. Each patient receives a placebo, B. Each patient receives both (double) treatments, C. The patients do not know which treatment they are receiving, D. The patients do not know that they are in a drug trial', 'role': 'user'}, {'content': "Answer: C \nExplanation: The double blind trial is so planned that neither the doctor nor the paicipant is aware of the group allocation and the treatment received. Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 91", 'role': 'assistant'}]