Which of the following processes is known as sanitization?

Assessing the risk involved in discarding information describes a risk management or information classification activity, not the sanitization process itself.

Verifying the identity of a person, network host, or system process is the definition of authentication, a completely separate security concept from data sanitization.

Physically destroying the media is specifically termed 'destruction' and is one disposal method - sanitization more broadly refers to data removal techniques that may not require physically destroying the media.

Sanitization specifically refers to the deliberate process of removing or making unrecoverable the data stored on media, using methods such as overwriting, degaussing, or cryptographic erasure. NIST SP 800-88 defines media sanitization as actions taken to render access to target data infeasible for a given level of effort, which directly corresponds to making content difficult or impossible to restore.