Clue 1: A unicellular organism

Clue 2: Lives in the human body

What is the correct classification of the organism?

Domain Bacteria; Kingdom Eubacteria
Domain Archaea; Kingdom Eubacteria
Domain Bacteria; Kingdom Archaebacteria
Domain Archaea; Kingdom Archaebacteria

The correct classification of the organism would be: Domain Bacteria; Kingdom Archaebacteria