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: Pharmacology
[{'content': 'A 24-year old pregnant women developed a gingival infection that appears to be a bacterial origin. Which of the following drugs is safe to be used in this patient? \nSelect and explain. \nA. Ampicillin, B. Clarithromycin, C. Sulfadiazine, D. Tetracycline', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]