This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Physiology
[{'content': "Nissl's bodies located intracytoplasmic are in \nSelect and explain. \nA. Perikaryon of neuron, B. Smooth muscle, C. Skeletal muscle, D. Cardiac muscle", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Nissl bodiesLarge granular bodies that stain with basic dyes, forming the reticular substance of the cytoplasm of neurons, composed of rough endoplasmic reticulum and free polyribosomes.Ref: Ganong&;s review of medical physiology; 24th edition', 'role': 'assistant'}]