A.run a procedure to check the tablespace space usage
B.define the warning threshold for the tablespace at 75% in Database Control
C.create a trigger to be executed when tablespace space usage reaches 75%
D.submit a job by using DBMS_JOB package to check the free space in the tablespace at regular intervals
E.define the warning threshold to be 75% for the tablespace by ALTER TABLESPACE .. ADD THRESHOLD command