This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: parasitology, Subject name: Microbiology
Which of the following is a sexually transmitted protozoan? 
Select and explain. 
A. Entamoeba histolytica, B. Toxoplasma gondii, C. Trypanosoma cruzi, D. Trichomonas vaginalis
D: Trichomonas vaginalis
Answer: D: Trichomonas vaginalis 
Explanation: Intestinal protozoaGiardia lamblia (flagellate)Entamoeba histolytica (ameba)Cryptosporidium hominis (sporozoa)Cyclospora cayetanensis (sporozoa)Sexually transmitted protozoan infectionTrichomonas vaginalis (flagellate)Blood and tissue protozoan infectionsSporozoaPlasmodium vivax, Plasmodium falciparum, Plasmodium ovale,and Plasmodium malariaeBabesia microtiToxoplasma gondiiMicrosporidiaAmebaeEntamoeba histolytica (see intestinal protozoa)Naegleria fowleri and Acanthamoeba castellaniiFlagellatesTrypanosoma brucei rhodesiense and Trypanosoma brucei gambienseTrypanosoma cruziLeishmania donovani, Leishmania tropica, Leishmania mexicanaRef: Jawetz Medical Microbiology; 27th edition; Page no: 710