What will happen to a person if they are o blood type and receive b blood?

A person with blood group O cannot receive blood from a person with blood group B. This is because the O blood group lacks the B antigen, and if they were to receive blood from a B blood group, their immune system would attack the B antigens on the donor red blood cells, causing a transfusion reaction. This can lead to serious health problems, including kidney failure and even death.