Answer
c. They are all parasitic.
Work Step by Step
Prokaryotes are both archaea and bacteria. They are fully functioning, living, single celled organisms. They evolved early in history in life and unlike eukaryotes, they lack a nucleus. Despite the fact that some bacteria may be parasitic, not all prokaryotes are parasitic. Cyanobacteria, for example, is not parasitic. Therefore, what is not true about prokaryotes is c. They are all parasitic.