Each cog takes a lot of resources to build, so they're made deliberately and with a purpose. The purposes can range from being a worker of menial labor to just being a companion or living prop and more. In order for a cog to be built, they have to have a sponsor, which is someone (another cog, usually a rich and powerful one) who paid for them to be made with an intended motive in mind.
Acolytes (rank B), bosses (rank C), and their entourage (rank D) are responsible for the creation of tall and powerful rank E cogs, or normal citizens, and they often sponsor rank F cogs, which are flunkies and goons. The powerful rank E cogs will often sponsor weaker rank E cogs.
If a sponsor is unknown, "unknown" will be put down; if they have definitely sponsored their own cogs but they're unknown, "unknown" will be put down; if its known for sure that they haven't sponsored their own, "na" (not available) will be put down.