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
A couple, with a fimily history of beta thalassemia major in a distant relative, has come for counseling. The husband has HbA2 of 4.8% and the wife has HbA2 of 2.3%. The risk of having a child with beta thalassemia major is - 
Select and explain. 
A. 50%, B. 25%, C. 5%, D. 0%
D: 0%
Answer: D: 0% 
Explanation: Ans. is 'd' i.e., 0%