Explanation
Amoebiasis is caused by Entamoeba histolytica.
It is a parasitic infection that can cause severe diarrhea and dysentery, as well as liver abscesses and other complications. Plasmodium vivax is the parasite that causes malaria, while Entamoeba gingivalis is a non-pathogenic amoeba that is found in the human mouth. Trypanosoma gambiense is a parasite that causes African sleeping sickness. Therefore, the correct answer is C: Entamoeba histolytica.