You are creating a cluster. The tables in the cluster have a relatively uniform distribution of values in the index column and the queries against the clustered table will almost use an equality operator to retrieve the desired row. Which type of cluster will you create？（）

You issued the following command：  
ALTER TABLE SCOTT.EMP SHRINK SPACE；  
The SCOTT.EMP table is stored in the DATA1 tablespace that has the following properties：  
DATA1 is a read/write tablespace.  
DATA1 is not autoextensible to an unlimited size.  DATA1 is online.  
Segment space management for the DATA1 tablespace is manual.  
You issued the ALTER TABLE SCOTT.EMP SHRINK SPACE； command that generates the following error：  
ORA-10635： Invalid segment or tablespace type  
 What could be the reason for the failure of the command？（）

You executed the following code：  
SQL> CREATE TABLE COUNTRY  
（COUNTRY_ID CHAR（2） CONSTRAINT COUNTRY_ID_nn NOT NULL，  
COUNTRY_NAME VARCHAR2（20），  
CURRENCY_NAME VARCHAR2（20），  
CONSTRAINT COUNTRY_ID_PK PRIMARY KEY （COUNTRY_ID））  
ORGANIZATION INDEX；  
In which tablespace will the mapping table be created？（）