This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': "Selective medium for Gonococci rpt \nSelect and explain. \nA. Thayer - main medium, B. LJ medium, C. DCA medium, D. MacConkey's medium", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Question repeated.', 'role': 'assistant'}]