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
Chance of having cystic fibrosis if only one parent is affected and other is normal 
Select and explain. 
A. 25%, B. 50%, C. 70%, D. 80%
B: 50%
Answer: B: 50% 
Explanation: Ans. is 'b' i.e., 50%