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': 'Which of the following cephalosporin is not active against anaerobes: \nSelect and explain. \nA. Cefoperazone, B. Cefotetan, C. Cefmetazole, D. Cefoxitin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]