Which two statements regarding unusable indexes are correct? (Choose two.)
A.
Your Data Definition Language (DDL) statement shows a warning message when an
index is made unusable.
B.
You do not need to set any parameter because unusable indexes are skipped
automatically.
C.
You can check the alert log file to get a message recorded about unusable indexes.
D.
You can set SKIP_UNUSABLE_INDEXES to true to skip unusable indexes.