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': 'Rgarding experimental studies, in a randomized controlled trial (RCT) all are true, EXCEPT: \nSelect and explain. \nA. Baseline characteristics are comparable, B. Bias can be eliminated by double blinding, C. Sample size depends on the type of study, D. Dropouts are excluded from the study', 'role': 'user'}, {'content': "Answer: D \nExplanation: In randomized controlled trial, some losses to follow-up are inevitable due to factors, such as death, migration and loss of interest. This is known as attrition. If the attrition is substantial, it may be difficult to generalize the results of the study to the reference population. Every effo, therefore should be made to minimize the losses to follow-up. Ref: Park's Textbook of Preventive and Social medicine, 19th edition, Page 76-78.", 'role': 'assistant'}]