Thermococcus, Methanococcus and Methanobacterium exemplify
Archaebacteria that contain protein homologous to eukaryotic core histones
Archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled
Bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria
Bacteria that contain a cytoskeleton and ribosomes
Inspection of domain Archaea shows that two sub-divisions exist, the Euryarchaeota and the Crenarchaeota. The Euryarchaeota includes Methanobacterium, Methanococcus, Thermococcus. Hence, the correct answer is option1