This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'The formation of 25-hydroxycholecalciferol takes place in the - \nSelect and explain. \nA. Liver, B. Kidney, C. Intestines, D. Pancreas', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]