A user executes a query on the EMP table， which contains thousands of rows， to get details about employees in one of the departments. The user receives the following error： SQL> SELECT ename FROM emp WHERE deptno=10 ORDER BY sal; SELECT ename FROM emp WHERE deptno=10 ORDER BY sal  *  ERROR at line 1：  ORA/x7f01157： cannot identify/lock data file 201 /x7f see DBWR trace file  ORA/x7f01110： data file 201： ’/u01/app/oracle/oradata/orcl/temp01.dbf’  What is a possible reason？（）

• A、The tempfile belonging to the default temporary tablespace is missing.
• B、The database is opened in restricted mode， so queries are not allowed.
• C、The default temporary tablespace required to execute the query is offline.
• D、The default temporary tablespace required to execute the query is dropped.
• E、The default temporary tablespace required to execute the query is read­only.