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: Medicine
[{'content': 'Gene mutations in Cystic fibrosis occurs at \nSelect and explain. \nA. Short arm of chromosome 7, B. Long arm os chromosome 5, C. Long arm of chromosome 7, D. Short arm of chromosome 3', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]