Final answer:
The claim that SQL*Plus issues an explicit COMMIT upon exit is false. It is up to the user to commit changes before exiting to ensure they are saved.
Step-by-step explanation:
The statement that a COMMIT is explicitly issued when the user exits SQL*Plus is false. When you exit SQL*Plus, it does not automatically issue a COMMIT. Any changes made to the database that have not been explicitly committed will be lost. It is the user's responsibility to issue a COMMIT before exiting if they wish to save the changes. It is worth noting, however, that if you use the 'EXIT' or 'QUIT' command in SQL*Plus and there are uncommitted transactions, SQL*Plus will prompt you whether to commit or not before exiting.