This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
[{'content': 'Protein A of Staphylococcus aureus is a pa of \nSelect and explain. \nA. Cell wall, B. Genome, C. Limiting membrane, D. Plasmid', 'role': 'user'}, {'content': "Answer: A \nExplanation: Protien A, is the cell surface protien, present in most S.aureus strains, has many biological propeies, including chemotactic, antiphagocytic and anti-complementary effects. IT also induces platelet damage and hypersensitivity. Ref: Textbook of Ananthanarayan and paniker's; 10th Edition; Pg:203", 'role': 'assistant'}]