Answer:
The women would be heterozygous for the blood type B.
Step-by-step explanation:
For the child to develop blood type A, the mother should be heterozygous for the blood type B.
B O
A AB AO
B BB BO
Hence, the results from this punnet square tell that the a mother heterozygous from blood type B when crossed with a father having blood type AB, will have the probability to produce 25% AB type, 25% AO type, 25% BB type and 25% B0 type offsprings. This type of punnet square will be blood testing punnet square.