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
What is the chance of having Homocystinuria if only one parent is affected and the other is normal? 
Select and explain. 
A. 25%, B. 0%, C. 50%, D. 75%
B: 0%
Answer: B: 0% 
Explanation: Homocystinuria is autosomal recesive disorder.If one parent is affected and the other is normal,none of the children will be affected.