Which of the following are not included in the stack layers of classical extensibility?

In the context of classical extensibility in software design, the stack layers typically consist of various components that facilitate the modular expansion and integration of functionalities within applications. The correct choice, which indicates that "Executive" is not included as a stack layer, is valid based on the conventional structure of these layers.

The stack layers generally encompass aspects such as Data, which deals with the storage and management of information; Visual, which pertains to the user interface and presentation layer; and Middle, which serves as the intermediary layer connecting the data and the visual components, often involving business logic and application services.

The term "Executive" does not correspond to a recognized layer in this architecture. Instead, it may refer to a broader concept of control or management within a system but does not fit as a layer in the classical extensibility stack. Understanding these layers is crucial for properly implementing extensibility in applications, as it allows developers to identify where to add or modify features without disrupting existing functionality.