This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable Diseases, Subject name: Social & Preventive Medicine
[{'content': 'Safe injection strategy will reduce the occurance of: \nSelect and explain. \nA. Hepatitis B, B. Hepatitis A, C. Typhoid, D. Hepatitis E', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans: a (Hepatitis B) Ref: Park, 19 ed, p. 179Not much to explain. All the others--hepatitis E, typhoid, hepatitits A, are water-borne diseases.', 'role': 'assistant'}]