Final answer:
A person with B− blood can receive compatible transfusions from donors with B− and O− blood types, as O− is the universal donor and both lack Rh antigens.
Step-by-step explanation:
A person with blood type B negative (B−) during a transfusion can receive blood from donors with type B negative (B−) and type O negative (O−). These blood types are compatible because type B negative blood does not have the A antigen and the Rh antigen, and similarly, type O negative is the universal donor with no A, B, or Rh antigens. It's important to note that while a universal donor can donate to any blood type, recipients must still receive compatible Rh factor blood, which in this case is negative (Rh−).