To answer this question, we need to understand how a job can send a status message to a TSO (Time Sharing Option) user at the completion of a job.
Option A) STATUS - This option is incorrect. The STATUS command is used to check the status of a job, but it does not send a status message to a TSO user at the completion of a job.
Option B) NOTIFY - This option is correct. The NOTIFY command is used to send a status message to a TSO user at the completion of a job. By specifying NOTIFY=USERID, the job will send a completion message to the specified TSO user.
Option C) ENDMSG - This option is incorrect. The ENDMSG parameter is used to specify the message that is to be displayed at the end of a job, but it does not send a status message to a TSO user.
Option D) USER - This option is incorrect. The USER parameter is used in the JOB statement to specify the user ID for the job, but it does not send a status message to a TSO user.
The correct answer is B) NOTIFY. This option is correct because the NOTIFY command is used to send a status message to a TSO user at the completion of a job.