Detailed Explanation:

Blood group is determined by specific antigens present on the surface of red blood cells (RBCs), not by haemoglobin, WBC/RBC combination, or RBC shape.

The ABO system uses A and B antigens (Type A has A antigen, Type B has B antigen, Type AB has both, Type O has neither), while the Rh system uses the D antigen (present = Rh-positive, absent = Rh-negative).

Haemoglobin carries oxygen and does not determine blood group; WBC/RBC combination refers to cell counts, not blood typing; RBC shape is related to disorders like sickle cell anemia, not blood group determination.