Refer to the exhibit. Which two statements about the SDF Locations window of the IPS Rule wizard are true？（）

• A、An HTTP SDF file location can be specified by clicking the Add button.
• B、If all specified SDF locations fail to load， the signature file that is named default.sdf will be loaded.
• C、The Autosave feature automatically saves the SDF alarms if the router crashes.
• D、The Autosave feature is automatically enabled for the default built-in signature file.
• E、The name of the built-in signature file is default.sdf.
• F、The Use Built-In Signatures （as backup） check box is selected by default.