What governs the governmental units that became counties in Georgia?

The correct answer focuses on the concept of representation from parishes, which relates to the historical organization of local governance in Georgia. In the early formation of what would become counties, the governance structure was influenced by the parish system, largely inherited from English colonial practices. Parishes served as basic geographical and administrative divisions that enabled effective representation and organization of communities.

As Georgia transitioned from these parishes to a county system, the emphasis on representation allowed for civilian governance that aligned with the interests and needs of the local population. This historical context emphasizes how such representation fostered local self-governance and ensured that the residents had a voice in their county's administrative matters.

The other options do not accurately capture the historical and administrative framework from which counties emerged in Georgia. Delegation from towns does not reflect the broader organizational structure meant for larger governance areas. Command by colonial governors implies a top-down approach that lacks the community representation aspect essential to county formation. Census-based districting does relate to representation, but it is more modern and does not pertain to the historical roots of counties in Georgia. Hence, representation from parishes is the most fitting explanation for how governmental units evolved into counties in Georgia.