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': 'The basis of combining ritonavir with lopinavir : \nSelect and explain. \nA. Pharmaceutical compatibility, B. CYP3A4 inhibition by ritonavir, C. Long elimination half life of ritonavir, D. Ability to counteract side–effects of lopinavir', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]