A pregnant woman had her blood group identified. Reaction of erythrocyte agglutination with standard serums of 0αβ (I), Bα (III) groups didn't proceed with standard serum of Aft (II) group. The blood group under examination is:

Answer options

1. Аβ (II)
2. -
3. Вα (III)
4. АВ (IV)
5. 0αβ (I)

Explanation

Blood group O (I): has no antigen and therefore no agglutination. Blood group A (II): has A-antigen, agglutinate with blood group B and blood group O. Blood group B (III): has B-antigen, agglutinate with blood group A and blood group O. Blood group AB (IV): has A and B antigen, agglutinate with all blood groups. No antibody was present. Antigen-D means Rhesus factor and since its negative, it is Rh-