What does the back rack do in relation to the tailboard?

The back rack serves the essential function of holding bundles of bags, which are necessary for packaging customer purchases. This organization is crucial in retail environments where efficiency is important for customer service. By keeping bags readily accessible, the back rack allows cashiers to quickly and effectively package items for customers, thereby facilitating a smoother checkout process. Additionally, having a dedicated space for bundling bags optimizes the workspace and keeps the area organized, which is beneficial for both staff and customers.

In contrast, the other functions mentioned in the options are not accurate representations of the back rack's purpose. The back rack is not designed to hold individual product bags, dispense items, or support the cash register, which are implications of other answers. This distinction highlights the specific role that the back rack plays in the overall operation and efficiency of the checkout area.