This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Anatomy
[{'content': 'Bence Jones proteins are \nSelect and explain. \nA. Light chain, B. Heavy chain, C. Medium chain, D. All of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: refer Robbins 9/e p965 Bence Jones proteins are made of light chain', 'role': 'assistant'}]