Which ABO phenotype selection contains the most H antigen and the least H antigen respectively on the red cell surface?

The ABO phenotype that contains the most H antigen on the red cell surface is the O phenotype, as individuals with this phenotype have the highest concentration of H antigen and lack A and B antigens. Conversely, the AB phenotype contains the least H antigen because it has both A and B antigens, which are produced by the modification of H antigen, resulting in a lower amount of unmodified H antigen on the surface.