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': "Which of the following statements about 'Simple Random Sampling' is true? \nSelect and explain. \nA. Sampling is based on similar characteristics, B. Suitable for large heterogeneous population, C. Complete list of items within the sampling frame is not required, D. Every element in the population has an equal probability of being included", 'role': 'user'}, {'content': "Answer: D \nExplanation: Simple random sampling is done by assigning a number to each of the units in the sampling frame. A table of random numbers is used. With this procedure, each unit has an equal chance of being drawn in the sample. It provides the greatest number of possible samples. Ref: Park's Textbook of Preventive and Social Medicine By K. Park, 19th Edition, Page 702; Research Methodology: Methods and Techniques By C. R. Kothari, 2nd Edition, Page 60", 'role': 'assistant'}]