If the following events were placed in chronological order, which would come fourth?

The answer is E. Water is contaminated (B) by human faeces containing cysts; the cysts release 4 motile trophozoites in the intestine (D). If these are pathogenic they cause necrosis of intestinal cells (C), and invade the submucosa entering the portal blood stream (E) and resulting in a hepatic abscess (A).