Which two statements regarding the above command are correct?

You executed the following command on a partitioned table sales_test:

ALTER TABLE sales_test
MOVE PARTITION s_q3 TABLESPACE users2
UPDATE INDEXES
(sales_test_ix
(PARTITION s_q3 TABLESPACE example) );

Which two statements regarding the above command are correct? (Choose two.)

A.
The sales_test_ix index will be rebuilt automatically.

B.
The UPDATE INDEXES clause is optional in the above command.

C.
The UPDATE INDEXES clause is used only with the MOVE operation on a partition.

D.
The UPDATE INDEXES clause without storage attributes will rebuild the index in the SYSTEM tablespace.

Explanation:
On the statement, de clause UPDATE INDEXES had been used. By default, many table maintenance operations on partitioned tables invalidate (mark UNUSABLE) the corresponding indexes or index partitions. You must then rebuild the entire index or, in the case of a global index, each of its partitions. The database lets you override this default behavior if you specify UPDATE INDEXES in your ALTER TABLE statement for the maintenance operation. Specifying this clause tells the database to update the index at the time it executes the maintenance operation DDL statement.

REF: Oracle(r) 10g Administrator Guide, 17-24