多项选择题 In your multitenant container database (CDB) containing same pluggable databases (PDBs), you execute the following commands in the root container: Which two statements are true?（）

多项选择题 You have altered a non-unique index to be invisible to determine if queries execute within an acceptable response time without using this index. Which two are possible if table updates are performed which affect the invisible index columns?（）

多项选择题 You use the segment advisor to help determine objects for which space may be reclaimed. Which three statements are true about the advisor given by the segment advisor?（）