This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable Diseases, Subject name: Social & Preventive Medicine
[{'content': 'Pleomorphism is seen in: \nSelect and explain. \nA. Chickenpox, B. Rubella, C. Smallpox, D. Toxocara', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (Chickenpox): Ref: (134-Park 20th)* Chickenpox shows pleomorphic rash i.e. different stages of the rash evident at one given time because rash appears in successive crops', 'role': 'assistant'}]