This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Forensic Medicine
[{'content': 'Corneal tattooing may be done with \nSelect and explain. \nA. Gold chloride, B. Calcium chloride, C. Copper sulfate, D. Potassium permanganate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Gold chloride Ref ; Narayana reddy 33rd ed.', 'role': 'assistant'}]