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': 'While halo or line around enamel margin in composite\nrestoration is not due to \nSelect and explain. \nA. Low intensity light curing, B. High intensity light curing, C. Inadequate etching and bonding, D. Traumatic contouring', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]