Answer:b; exocytosis
Explanation: leukocytes are amoeboid white blood cells, which are involved in immune response .such response included combating foreign bodies like micro organisms which invade the body.they do this by engulfing the micro organisms and digesting them.
Phagocytosis, pinocytosis, receptor mediated endocytosis are the ways in which the cells engulfs the Invaders.
In endocytosis,the membrane of the cell traps the organism by forming an invagination.it then encloses the micro organism and digests it.
