This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
[{'content': 'Superantigen is produced by \nSelect and explain. \nA. Staphylococcus aureus, B. Streptococcus pneumoniae, C. Pseudomonas aeruginosa, D. Clostridium diphtheriae', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Superantigens are that antigen which can generate the high immune response upon introduction', 'role': 'assistant'}]