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
Chromosome 7 involvement is seen in: 
Select and explain. 
A. Osteosarcoma, B. Osteosarcoma, C. Cystic fibrosis, D. Colon Ca
C: Cystic fibrosis
Answer: C: Cystic fibrosis 
Explanation: Cystic fibrosis