The CURSOR_SHARING parameter is set to SIMILAR at the instance level and you issue these SELECT statements in the order shown below：  
SELECT * FROM employees WHERE department_id=50； 
SELECT * FROM employees WHERE department_id=70；
There is an index on the DEPARTMENT ID column of the 1，000，000 row EMPLOYEES table. Ninety percent of the employees are part of the DEPARTMENT_ID 50. In which two scenarios will Oracle9i share the corresponding cursors for the two statements？（）

A.The initial request from the client to the listener.
B.Messages between the dispatcher and the shared server background processes.
C.A redirect message from the listener to the client during client connections.
D.Round-trip messages between the listener and the shared server background processes.

A.SWITCH_TIME
B.SWITCH_GROUP
C.MAX_SESS_POOL
D.SWITCH_ESTIMATE

A.Only MEMORY is updated.
B.Only SPFILE values are updated.
C.Only init.ora parameters are updated.
D.Both init.ora parameters and SPFILE values are updated.