This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Medicine
[{'content': 'In cystic fibrosis the most common organism which causes infection is \nSelect and explain. \nA. Pseudomonas, B. Staphylococcus, C. Kiebsiella, D. Streptococcus', 'role': 'user'}, {'content': "Answer: B \nExplanation: Respiratory infections are characteristic feature of cystic fibrosis in the presence of viscous secretions blocking medium and small airways.The most common organism is Staphylococcus aureus.Other organisms include H.influenza,Pseudomonas aeruginosa,etc. Ref:Harrison's med:18th edition,page no:1697.", 'role': 'assistant'}]