Final answer:
Receptor-mediated endocytosis is a selective form of endocytosis that uses receptors on the cell membrane to bring specific substances into the cell. It can follow the pathway of either clathrin-mediated endocytosis or caveolae-mediated endocytosis.
Step-by-step explanation:
Receptor-mediated endocytosis is a form of endocytosis that relies on the affinity of receptors for specific extracellular substances. It involves the aggregation of receptors in coated pits on the cell membrane, which then invaginate and pinch off to form a coated vesicle. This process allows the cell to selectively bring larger substances into the cell. Receptor-mediated endocytosis can follow the pathway of clathrin-mediated endocytosis, which involves the use of clathrin-coated pits and vesicles, or caveolae-mediated endocytosis, which involves the use of caveolae. Therefore, the answer to the question is c. Both a and b.