Final answer:
The correct statement regarding control charts is D. Control charts are used to distinguish whether the process is operating normally or requires attention.
Step-by-step explanation:
Control charts are used to distinguish whether the process is operating normally or requires attention.
Control charts are graphical tools used in statistical process control to monitor and analyze the performance of a process over time.
They help identify whether a process is in control, meaning it is operating within acceptable limits, or if there are any special causes of variation that require investigation and corrective action.