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: Surgery
[{'content': 'Actinomycosis is caused by \nSelect and explain. \nA. Gram +ve filamentous Bacteria, B. Gram –ve filamentous bacteria, C. Fungi, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Actinomycosis is caused by Actinomyces israeli,, an anaerobic gram positive filamentous organism.\nMicroscopy reveals characteristic sulphur granules in the pus.\nThe four clinical forms of actinomycosis are cervico-facial (commonest), ileocaecal, thoracic and in liver.\nPenicillin is the drug of choice in treating actinomycosis.', 'role': 'assistant'}]