Which of the following is true regarding a CDT's name and namespace?

A complex data type (CDT) in Appian has certain properties regarding its name and namespace that are critical for its usage and management. Once a CDT is created, the name and namespace are fixed and cannot be altered. This immutability ensures that existing references to the CDT remain valid and that the data structure's integrity is maintained throughout the application's lifecycle.

When a CDT is referenced in various parts of an application, any change to its name or namespace would lead to broken links or variable mismatches, which can result in errors. Therefore, developers must choose a meaningful and appropriate name and namespace during the creation phase since changes are not permissible thereafter.

The other options suggest that changes can be made or that the name and namespace are optional or need to be unique across environments, which does not accurately describe their properties in Appian. The requirement for uniqueness pertains to the namespace within a specific environment, but it does not imply a need for change after creation.