A user executes a query on the EMPtable， 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-01157： cannot identify/lock data file  201 - see DBWR trace file ORA-01110： 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 read-only.