Which two statements are true about space-saving features in an Oracle Database?

Private Temporary Tables (PTTS) store metadata in memory only

An index created with the UNUSABLE attribute has no segment

If they exist for a session, Private Temporary Tables (PTTs) are always dropped at the next COMMIT OR ROLLBACK statement

An index that is altered to be UNUSABLE will retain its segment

A table that is truncated will always have its segment removed