C# Error CS1906 – Invalid option ‘{0}’; Resource visibility must be either ‘public’ or ‘private’

C# Error

CS1906 – Invalid option ‘{0}’; Resource visibility must be either ‘public’ or ‘private’

Reason for the Error & Solution

Invalid option ‘option’; Resource visibility must be either ‘public’ or ‘private’

This error indicates an invalid or command line option. Check the syntax of the /resource or /linkresource command line option, and make sure that the accessibility modifier used is either public or private.