The answer is b. Protists can be prokaryotes or eukaryotes.
The Protista kingdom contains eukaryotic organisms that do not belong to the Kingdoms of Fungi, Plantae or Animalia. These organisms could be multicelled (eg. kelp, slime molds, red algae) or single-celled (Paramecium). They can live in freshwater or saltwater environments either as autotrophs or heterotrophs.
