What is responsible for the different blood types in humans? select one:
a. three or four proteins attached to a membrane monosaccharide on the surface of red blood cells.
b. three or four monosaccharides attached to a membrane protein on the surface of red blood cells.
c. three or four amino acids attached to a membrane monosaccharide on the surface of red blood cells.
d. three or four lipids attached to a membrane polysaccharide on the surface of red blood cells?