The nexus category is necessary information required when registering for a .us top-level domain (TLD). You will be required to select a Nexus Category during the process. There are multiple choices available, and you'll want to select the one that best describes you or the entity you represent.
C11 -A United States Citizen.
C12 -A permanent resident of the United States or any of its territories.
C21 -An organization incorporated within the United States.
C31 -An entity that regularly engages in lawful activities in the United States.
C32 -An entity that has an office or facility in the United States.