The datafiles of your database are ASM files. You are performing a check for datafile block corruption by using the DBVERIFY utility.   What is a prerequisite for checking block corruption on an ASM datafile by using the DBVERIFY utility？（）  

• A、 The block change tracking feature must be enabled.
• B、 OMF must be configured on your database.
• C、 The database must be in ARCHIVELOG mode.
• D、 A USERID must be supplied.