Which two statements are true regarding the functionality of the remap command in ASMCMD？（）

• A、 It repairs blocks that have read disk I/O errors.
• B、 It checks whether the alias metadata directory and the file directory are linked correctly.
• C、 It repairs blocks by always reading them from the mirror copy and writing them to the original location.
• D、 It reads the blocks from a good copy of an ASM mirror and rewrites them to an alternate location on disk if the blocks on the original location cannot be read properly.