To determine if their offspring can have type A blood, we need to use a Punnett square to see all the possible combinations of their alleles.
The male has type AB blood, which means he has alleles IA and IB.
The female has type O blood, which means she has alleles ii.
Let's set up the Punnett square:
| i | i |
-----------------------
IA | IAi | IAi |
-----------------------
IB | IBi | IBi |
-----------------------
From the Punnett square, we can see that there are four possible combinations of alleles for their offspring:
1. IAi
2. IAi
3. IBi
4. IBi
Two out of the four possibilities result in the presence of allele A (IA), which means it is indeed possible for their offspring to have type A blood.