Which of the following exemplifies a control that allows for a readjusted set point?

A submaster controller is designed to manage multiple set points within a system. By definition, it allows for adjustments to be made to operational parameters, including the readjustment of set points based on feedback from the system. This capability is integral in applications where fine-tuning of performance is required, enabling operators to optimize system behavior in response to a variety of operational conditions.

In contrast, a main controller typically oversees the broader control system but does not specifically handle modifications to set points. A direct control switch simply provides on/off commands without any feedback mechanisms or the ability to readjust set points. A feedback stabilizer uses input from the system's performance to maintain stability, but it primarily stabilizes an existing set point rather than modifying it. This distinct function of the submaster controller to adjust and manage set points is why it represents the correct answer for this question.