How does confidentiality protect people and their online activity against potentially dangerous or problematic information? by immediately altering or deleting sensitive data so that it cannot be accessed ever again
by blocking your data access by messing with the basic hardware or systems at work
through the use of passwords, account numbers, verification codes, or other preventative methods
by instantly repairing operating systems to keep them working properly and providing disaster recovery and system upgrades

Through the use of passwords, account numbers, verification codes, or other preventative methods

Explanation:

Everyone who actively uses the internet should be careful about who could have access to their information. This applies to everything from photos to credit card information, because you never know who could be trying to use it. What protects your information are passwords, account numbers, verification codes, and other preventative methods. No one can instantly delete sensitive data, block your data access by messing with hardware, or instantly repair operating systems. Technology has simply not gone far enough, so passwords and similar methods are the best options we have when it comes to the protection of our sensitive information.

●intensive purposes is the correct answer