You have configured flash recovery area in your database and you set the following Initialization parameters for your database instance：   LOG_ARCHIVE_DEST 1 = ，，LOCATION=/disk1/arch MANDATORY’  LOG _ARCHIEVE_DEST 2 = ，，LOCATION=/disk2/arch’ LOG_ARCHIVK_DEST_3 = ，，LOCATION=/diSk3/arch  LOG_ARCH1VK_DEST_4 = ’ LOCATION=/disk4/arch’  LOG_ARCHIVE_MIN-SUCCEED_DEST = 2   While the database instance is functional，you realized that the destination set by the  LOG_ARCHIVE_DEST_I parameter Is not available for the archived redo log file to be created in. All redo log groups have been used.  What happens in an event of log switch？（）  

• A、 The online redo log file Is not allowed to be overwritten.
• B、 The archived redo log files are written to the flash recovery area until the MANDATORY destination is made available.
• C、 The database instance will crash because the archived redo log file cannot be created in a destination set as MANDATORY.
• D、 The destination set by the LOG_ARCHIVE_DEST_1 parameter is ignored and the archived redo log files are created in the next two available locations to guarantee archive log success.