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: Pathology
[{'content': 'Chromosome defective in cystic fibrosis is - \nSelect and explain. \nA. Chromosome 5, B. Chromosome X, C. Chromosome 7, D. Chromosome 1', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The primary defect in cystic fibrosis results from abnormal function of an epithelial chloride channel protein encoded by the cystic fibrosis transmembrane conductance regulator (cfTR) gene on chromosome band 7q31.2.', 'role': 'assistant'}]