This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thanatology, Subject name: Forensic Medicine
[{'content': "Nysten's rule is for the order of \nSelect and explain. \nA. Rigor mois, B. Post Moem staining, C. Algor Mois, D. Cadaveric spasm", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Nysten\'s law: Nysten\'s law deals with the progression of rigor mois It first affects the involuntary muscles staing with the myocardium The order of appearance in voluntary muscles is: Upper eyelids, Neck muscles, Jaw, Facial muscles, Chest Upper limbs, Abdomen Lower limbs Finger and toes. Order of disappearance is also the same. Rigor mois follows the "rule of 12"- 12 hrs to set in, remains for 12 hrs, and passes off in 12 hrs.', 'role': 'assistant'}]