This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Death and postmortem changes, Subject name: Forensic Medicine
[{'content': "Nysten's rule peains to - \nSelect and explain. \nA. Rigor mois, B. Identification, C. Bullet injuries, D. Putrefaction", 'role': 'user'}, {'content': "Answer: A \nExplanation: Nysten's rule states that Rigor mois does not sta in all muscles simultaneously, it appears first in involuntary muscles. Ref: K.S.Narayan Reddy's Synopsis of Forensic Medicine and Toxicology, 29th edition, Chapter 7, Page 88.", 'role': 'assistant'}]