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': 'True for effect of smoking on prognosis of periodontal diseases following scaling and prophylaxis is \nSelect and explain. \nA. Increase in clinical attachments, B. Increase in width of attached gingiva, C. Reduction in negative influence of smoking due to increased level of plaque control, D. Increase in neutrophilic response', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]