Which object type exposes a version history for the Developer to review?

The correct choice is related to Process Models, which indeed exposes a version history that developers can review. In Appian, Process Models are critical for orchestrating business processes and represent the flow of tasks and activities. As processes evolve over time, it’s essential for developers to maintain oversight of changes and updates. The version history feature allows them to track these changes, see who made modifications, and understand the evolution of the process design. This is particularly useful in maintaining compliance and ensuring that modifications do not negatively impact the process's integrity or performance.

The other object types do have their own importance and functionalities but do not provide a version history feature in the same way. For instance, Record Types are geared towards displaying and managing data rather than tracking changes over time. CDTs are structures for defining data but do not have an in-built version control mechanism. Similarly, Expression Rules are designed for encapsulating reusable logic and calculations but lack a detailed version history for developers to reference past iterations. Understanding the specific functionalities and purposes of each object type is essential for effective use and management within the Appian environment.