Which of the following can control the visibility of elements in Pega?

The ability to control the visibility of elements in Pega is primarily achieved through the use of when rules, conditions, and execution. When rules provide a logical framework for determining whether a certain condition is met, they can be effectively used to show or hide UI elements based on specific criteria. This dynamic control allows developers to create responsive interfaces that adjust according to the user's data or actions. For example, a when rule might be set to show a particular field only if a specific option is selected in a previous field.

In contrast, the other options do not cater to the direct management of element visibility in the same manner. Data types and page layouts define how data is structured and displayed, but they do not inherently provide conditional logic for visibility control. Process models and business rules focus on workflow and decision-making processes rather than UI presentation. Likewise, service endpoints and system configurations pertain to system interactions and backend settings rather than UI elements' visibility. Thus, the use of when rules is the most effective means of managing what users see in the Pega interface.