The explained experiment is the pulse-chase experiment in this the cells that are involved are macrophages. Macrophages are the immunity cells that have a large number of the lysosomes for killing the pathogens enters in the cell brought into the cell through the process of phagocytosis.
Phagocytosis takes place with the help of the enzyme called hydrolytic enzyme that is synthesized in the endoplasmic reticulum and modified by Golgi and moves to the lysosome.
Thus, the correct answer is option - phagocytosis.
