Which pair of parents could have offspring with blood group O?
- Aheterozygous father with blood group A and heterozygous mother with blood group B
- Bheterozygous father with blood group A and homozygous mother with blood group B
- Chomozygous father with blood group A and heterozygous mother with blood group B
- Dhomozygous father with blood group A and homozygous mother with blood group O