Which two statements are true about the effect of the above command?

Examine the command that is used to create a table:
SQL> CREATE TABLE orders(oid NUMBER(6) PRIMARY KEY, odate DATE, ccode
NUMBER (6), oamt NUMBER(10,2)) TABLESPACE users;
Which two statements are true about the effect of the above command? (Choose two.)

A.
A CHECK constraint is created on the OID column.

B.
A NOT NULL constraint is created on the OID column.

C.
The ORDERS table is the only object created in the USERS tablespace.

D.
The ORDERS table and a unique index are created in the USERS tablespace.

E.
The ORDERS table is created in the USERS tablespace and a unique index is created on the OID
column in the SYSTEM tablespace.