Final answer:
The P2 phenotype has the P antigen and the Pk antigen, indicated by option 2. Unlike the ABO blood group system, the P blood group system includes P1, P2, and Pk phenotypes based on different antigens.
Step-by-step explanation:
The P2 phenotype in the context of the Blood Group P System does not express the P1 antigen. Instead, it has the P antigen and the Pk antigen. Therefore, the correct answer is option 2: P and Pk. In comparison with the well-known ABO blood group system, which includes Type A, Type B, Type AB, and Type O based on the presence of antigens A and B, the P blood group system is defined by the presence of different antigens such as P1, P, and Pk. The phenotypes of this system are usually conveyed as P1, P2, and Pk, based on the combination and absence of these specific antigens.