The correct option is A Eubacteria
Eubacteria and Archaebacteria belong to kingdom Monera; whereas Protists belong to kingdom Protista. All Monerans have prokaryotic cell structure. Protists have eukaryotic cell structure and are unicellular. Amoeba, euglena are single celled organisms while the slime moulds are eukaryotic and all three come under protists.