ASMON would automatically restore the lost file.
BYou would need to restore the whole database from the last backup.
CYou would need to restore the file from the last full database backup.
DYou would need to use flashback technology to restore the lost redo log member.
EYou would need to use Recovery Manager (RMAN) to restore the lost redo log member.
FYou would need to restore the missing log file by copying one of the remaining files from the same group.