The inheritance of the ABO blood groups is controlled by three alleles $I^A$, $I^B$ and $I^O$. Which genotypes could a person with blood group A have?
- A$I^AI^A$ only
- B$I^AI^A$ and $I^AI^B$ only
- C$I^AI^A$ and $I^AI^O$ only
- D$I^AI^A$, $I^AI^O$ and $I^AI^B$