Which of the following describes static members in C++?

Static members in C++ are unique in that they are shared among all instances of a class. This means that regardless of how many objects of that class are created, there is only one copy of the static member, and all instances refer to that same copy. This is particularly useful for class-wide values that need to be consistent across all objects, such as counters or configuration settings.

The essence of a static member is that it is independent of object instances; thus, it does not get created or destroyed with the objects but rather exists at the class level. This allows all instances to access and modify the static member, making it ideal for information that needs to be universally accessible and consistent across all instances of the class.

In contrast, other options describe characteristics that do not apply to static members: access by derived classes, value retention across instances, and restrictions to local scope do not encapsulate the defining feature of static members correctly. Static members, by their nature, are not limited to any derived access or local scope but embody global accessibility at the class level.