Note the following functionalities of various background processes： 1：Record the checkpoint information in data file headers. CKPT 2：Perform recovery at instance startup. SMON 3：Cleanup unused temporary segments. SMON 4：Free the resources used by a user process when it fails. 5：Dynamically register database services with listeners. 6：Monitor sessions for idle session timeout. Which option has the correct functionalities listed for a background process（）

Archiver Process （ARCn）：1， 2，5
B. System Monitor Process （SMON）：1，4，5
C. Process Monitor Process （PMON）：4，5，6
Database Writer Process （DBWn）：1，3，4