The image below is from a fecal smear of an individual complaining of diarrhea and intestinal discomfort. The parasites were numerous and quite variable in size, but the majority measured about 15 to...

The image below is from a fecal smear of an individual complaining of diarrhea and intestinal discomfort. The parasites were numerous and quite variable in size, but the majority measured about 15 to 20 mm in diameter. What is the most likely identification of this organism?

a. Blastocystis hominis

b. Cyclospora cayetanensis

c. Isospora belli

d. Balantidium coli