You want to set the following initialization parameters for your database instance：   LOG_ARCHIVE_DEST_1 = ’LOCATION=/disk1/arch’ LOG_ARCHIVE_DEST_2 = ’LOCATION=/disk2/arch’ LOG_ARCHIVE_DEST_3 = ’LOACTION=/disk3/arch’ LOG_ARCHIVE_DEST_4 = ’LOCATION=/disk4/arch MANDATORY’   Identify the statement that correctly describes this setting.（）  

• A、 The MANDATORY location must be a flash recovery area.
• B、 The optional destinations may not use the flash recovery area.
• C、 This setting is not allowed because the first destination is not set as MANDATORY.
• D、 The online redo log file is not allowed to be overwritten if the archived log cannot be created in the fourth destination.