Single-celled eukaryotes are included in
(a) Protista (b) Fungi
(c) Archaea (d) Monera
Kingdom-Protista includes all unicellular eukaryotic organisms like flagellates, diatoms, dinoflagellate, slime mould, sarcodina, etc. Fungi represents a group of eukaryotic, achlorotrophic organisms of diverse forms, sizes, physiology and mode of reproduction. The members of Archaea (Archaebacteria) are prokaryotes and include the extreme halophiles, the thermoacidophiles and the methanogens.
Monera is the kingdom that in older clasifications contains all prokaryotes.