Answer -   This three alongwith name of the assembly provide a strong name or fully qualified name to the assembly. When a assebly is referenced with all three. PublicKeyToken: Each assembly can have a public key embedded in its manifest that identifies the developer. This ensures that once the assembly ships, no one can modify the code or other resources contained in the assembly. Culture: Specifies which culture the assembly supports   Version: The version number of the assembly.It is of the following form major.minor.build.revision. Explain the differences between public, protected, private and internal. These all are access modifier and they governs the access level. They can be applied to class, methods, fields. Public: Allows class, methods, fields to be accessible from anywhere i.e. within and outside an assembly. Private: When applied to field and method allows to be accessible within a class. Protected: Similar to private but can be accessed by members of derived class also. Internal: They are public within the assembly i.e. they can be accessed by anyone within an assembly but outside assembly they are not visible.