Use the Following Information to Answer the Following Question(s)

Use the following information to answer the following question(s) .
Malaria is an infectious disease caused by a unicellular eukaryotic organism belonging to the genus Plasmodium. These eukaryotic organisms are transmitted from one person to another by the female Anopheles mosquito when it feeds on human blood. Within humans, the Plasmodium spp. destroy red blood cells and, without effective treatment, serious infections can lead to death. Currently, more than 400 million people are afflicted with malaria and between 1 to 3 million people die from it each year. Historically, a chemical compound called quinine has been used in developing effective drugs against malaria. In its natural environment, quinine is produced by certain trees native to South America. This chemical is synthesized in the outer layer of tree trunks and acts as an herbivore deterrent.
-Based on the relationship between Plasmodium spp.and humans,these organisms would be considered ______.

A) parasites
B) hosts
C) producers
D) carnivores