Mastering C++: A Comprehensive Quiz Based on 'Thinking in C++'

Namespaces in C++ can be nested, meaning that a namespace declaration can be placed inside another namespace declaration. This allows for better organization and avoids naming conflicts within large code bases. Option B is incorrect because namespaces are identified by a unique name. Option C is incorrect because variable names can be scoped within namespaces, allowing for better organization of variables. Option D is incorrect because not only functions, but also variables, classes, and other objects can be defined within namespaces.