A child has blood group ‘O’ and her/his mother has blood group ‘A’, then what are the possibilities of blood group of her/his father ?  (A) ‘A’  (B) ‘B’  (C) ‘O’  (D) All of these
A child has blood group ‘O’ and her/his mother has blood group ‘A’, then what are the possibilities of blood group of her/his father ?  (A) ‘A’  (B) ‘B’  (C) ‘O’  (D) All of these

Answer: (D) All of these

Explanation: A blood test is performed to assess whether a blood sample contains the A and/or B features. A blood test result for type A or type B cannot be used to determine the actual genotype. A person with blood type A must have at least one copy of the A allele, however two copies are possible. They have one of two genotypes: AA or AO.