A Patient Presents with Symptoms of Severe Gastrointestinal Distress

A patient presents with symptoms of severe gastrointestinal distress. Bacterial and viral pathogens are ruled out. A protozoan which moves via hair- like appendages is observed upon microscopic examination of the patient's stool. The most likely cause of the infection is

A) Balantidium coli, a ciliated protozoan.
B) ergot toxin, a fungal mycotoxin.
C) Giardia lamblia, a flagellated protozoan.
D) Plasmodium, an apicomplexan.
E) Entamoeba histolytica, an amoeboid protozoan.