多项选择题
A. Create a custom section handler class that inherits the ConfigurationSection interface
B. Add a section element to the EmployeeSection element of the application configuration file
C. Create a custom section handler class that implements the IConfigurationSectionHandler interface.
D. Add an EmployeeSection element to the configSections element of the application confguration file
E. Create a custom section handler class that implements the IApplicationSettingsProvider interface
F. Add a section element to the configSections element of the application configuration file