Answer:
Domain
Explanation:
Domain is the least specific.
There three domains are:
* Bacteria - a prokaryote
* Archea - a prokaryote
* Eukarya - a eukaryote
Prokaryotes don't have a membrane-bound nucleus.
Eurkaryotes (including humans) have a membrane-bound nucleus.
The classification from least to most specific is:
Domain -> Kingdom -> Phylum -> Class -> Order -> Family -> Genus -> Species