This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
[{'content': 'All of the following cause inhibition of CYP3A except \nSelect and explain. \nA. Saquinavir, B. Ritonavir, C. Itraconazole, D. Erythromycin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: All the drugs given in the option are microsomal enzyme inhibitors .Among protease inhibitor,ritonavir the strongest inhibitor of CYP3A4 enzymes whereas saquanivir is the weakest', 'role': 'assistant'}]