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': 'Organs take pa in vitamin D formation \nSelect and explain. \nA. Liver, B. Skin, C. Kidney, D. All of the above', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Vitamin D is formed in skin with help of sunlight and activated in liver and kidneyRef: Ganong&;s review of medical physiology; 24th edition; page no: 380', 'role': 'assistant'}]