From where are custom exceptions derived from

SystemException and ApplicationException are both derrived from Exception.SystemException is the predefined base class for exceptions that originate from theSystem namespace.ApplicationException is the class intended as a base for any application specificexceptions that it is decided, need to be defined.If you want to define your own "exceptions" for your own specific applicationthen it is considered good practice to derrive your own "exception" class f
romApplicationExceptionpublic class CustomException : ApplicationException .