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': "Design Effect' is associated with which of the following sampling techniques - \nSelect and explain. \nA. Stratified sampling, B. Systemic sampling, C. Cluster sampling, D. Simple Random Sampling", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]