$ABO$ blood grouping is controlled by gene $I$,which has three alleles and shows co-dominance. There are six genotypes. How many phenotypes in all are possible?

As per the $ABO$ blood grouping system,the blood group of the father is $B^{+}$,the mother is $A^{+}$,and the child is $O^{+}$. Their respective genotypes can be:
Choose the most appropriate answer from the options given below:
$A. I^Bi / I^Ai / ii$
$B. I^BI^B / I^AI^A / ii$
$C. I^AI^B / iI^A / I^Bi$
$D. I^Ai / I^Bi / I^Ai$
$E. iI^B / iI^A / I^AI^B$

The number of phenotypes in $ABO$ blood group is

If a child has $O$ type of blood group and the father has $B$ type,the genotype of the father will be:

$A$ male with heterozygous blood group $B$ and a female with homozygous blood group $A$ have offspring. What are the possible genotypes and phenotypes in their progeny?

$ABO$ blood group is a good example of: