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: Dental
[{'content': 'Gap between true end of casting ring and wax pattern should be \nSelect and explain. \nA. ¼ inch, B. ½ inch, C. 3/8 inch, D. one inch', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]