An individual with which ABO blood type can theoretically donate blood to recipients of all ABO types?

An individual with type O blood can theoretically donate blood to recipients of all ABO types. This is because type O blood lacks A and B antigens on the surface of red blood cells, making it universally acceptable without triggering an immune response in recipients with A, B, AB, or O blood types. As a result, type O is often referred to as the universal donor.