Which blood type can donate blood to all other types?

The correct answer is O. Individuals with blood type O have what is known as universal donor status. This is because blood type O lacks A and B antigens on the surface of its red blood cells. As a result, type O blood can be transfused into individuals with any blood type—A, B, AB, or O—without triggering an immune response.

In contrast, blood types A, B, and AB possess specific antigens (A or B) that can elicit an immune response if transfused into someone without the corresponding type. For example, blood type A has A antigens, and people with this type can only safely receive A or O blood. Blood type AB, while being the universal recipient (able to receive A, B, AB, or O), cannot donate to all blood types due to its A and B antigens.

Thus, the compatibility of blood type O as a donor makes it unique for transfusions across all blood types.