6. A patient has a positive antibody screen and a positive antibody panel. All tested cells are positive (3+) at the AHG phase of reactivity. The only tested cell that is negative is the autocontrol. You phenotype the patient and discover that he is negative for the following antigens: E, Fy(a), S, and Jk(b). You locate a testing cell that has this antigen negative phenotype. The cell reacts 3+ at the AHG phase. Of the following choices, which is the most likely specificity of the antibody/antibodies?