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 family 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: HBA2 of 4.8% indicates beta thalassemia minor or trait.
HbA2 of 2.3% indicates normal person.
Thalassemia is an autosomal recessive disorder. Therefore, when a trait marries a minor, then the risk of having children with thalassemia major is 0%.