If a man with blood group A marries a woman with blood group AB. Which of the following blood group will never be found in their children?

O

The correct answer is Option (4) → O

The possible blood group combinations for the children of a man with blood group A and a woman with blood group AB.

• A man with blood group A can have two possible genotypes: AA or AO.
• A woman with blood group AB has the genotype AB.

We can consider the combinations using these genotypes:

1. If the man's genotype is AA:
• Possible offspring genotypes: AA, AB
2. If the man's genotype is AO:
• Possible offspring genotypes: AA, AB, AO, BO

From these combinations, the possible blood groups in their children can be:

• A (from AA or AO)
• B (from BO)
• AB (from AB)

The blood group O (which has the genotype OO) will never appear because neither parent can provide two O alleles.

Therefore, blood group O will never be found in their children.