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': 'Finish lines of a complete coverage crown should lie \nSelect and explain. \nA. Supragingivally, B. Subgingivally, C. Subgingival if required, D. Gingival margin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]