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': 'Structural classification of B-lactamases was given by: \nSelect and explain. \nA. Amber, B. Bush, C. Ross, D. Kennedy', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Amber gave molecular / structural classification, where B-lactamases are classified into 4 categories (A,B,C,D)\nBush gave funtional classification of B-lactamases.', 'role': 'assistant'}]