This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: recent papers  obst, Subject name: Gynaecology & Obstetrics
[{'content': 'Dose of benzanthine penicillin in early syphilis is _________ \nSelect and explain. \nA. 3-4 million units intravenously, B. 2.4 million units intramuscularly as a single injection, C. 2.4 million units intramuscularly daily, plus probenecid 500 mg orally for 14 days, D. 2.4 million units intramuscularly weekly for three doses', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 2.4 million units intramuscularly as a single injection is the dose of benzanthine penicillin early syphilis. Early syphilis: Benzanthine penicillin G, 2.4 million units intramuscularly weekly for three doses. More than 1-year duration: Benzanthine penicillin G, 2.4 million units intramuscularly weekly for three doses. Neurosyphilis: Aqueous crystalline penicillin G, 3-4 million units intravenously every 4 hours for 10-14 days or Aqueous procaine penicillin, 2.4 million units intramuscularly daily, plus probenecid 500 mg orally four times daily, both for 10-14 days. Ref: Willams Obstetrics 25th edition Pgno: 1238', 'role': 'assistant'}]