Question

How many possible genotypes are there for ABO blood groups in man?

• A. Three
• B. Four
• C. Six
• D. Eight

Answer 1

Answer: (C)

Six

Genotype	Blood types
$I^A{I}^O$ or $I^A{I}^A$	A blood type
$I^A{I}^B$	AB blood type
$I^B{I}^O$ or $I^B{I}^B$	B blood type
$I^O{I}^O$	O blood type

There are six possible genotypes for the ABO blood groups in human.
The chart here shows the different genotypes, that make up the blood groups.
Therefore, the correct answer is option C.