What does namespace contain?

MyNamespace::MyClass myObject;

You can also use namespaces to group related types together. For example, you might have a namespace for all of your user-defined types, and another namespace for all of your system types. This can help to keep your code organized and easy to read.

Here is a brief explanation of each option:

• Code that defines a group of related classes. This is the correct answer. A namespace is a way to group related identifiers together, which can be useful for avoiding name clashes, as well as for organizing code.
• Code to define hierarchy. This is not correct. A namespace does not define a hierarchy.
• Contains object definition. This is not correct. A namespace does not contain object definitions.
• Contains class definition. This is not correct. A namespace does not contain class definitions.