John works as a Network Administrator for Perfect Solutions Inc.

John works as a Network Administrator for Perfect Solutions Inc. The company has a Linux-based network. He is working as a root user on the Linux operating system. He wants to delete his private.txt file from his operating system. He knows that the deleted file can be recovered easily. Hence, he wants to delete the file securely. He wants to hide the shredding, and so he desires to add a final overwrite of the file private.txt with zero. Which of the following commands will John use to accomplish his task?