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: Social & Preventive Medicine
[{'content': 'Random is Randomization Implies \nSelect and explain. \nA. Unequal and known chances, B. Equal and known chances, C. Unequal and unknown chances, D. Equal and unknown chances', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]