The ORDERS table has a constant transaction load 24 hours a day, so down time is not allowed. The index become fragmented. Whic statment is true ?

The index need to be dropped, and then re-created.

The resolution of index fragmentation depends on the type of index.

The index can be rebuilt while users continue working on the table.

The fragmented can be ignored because Oracle resolve index fragmentation by means of a freelist.

The index can be rebuilt, but users will not have access to the index during this time.