Which of the following is a consequence of applying strong magnetic fields to data storage media?

Applying strong magnetic fields to data storage media results in degaussing, which is the process of reducing or eliminating the magnetic field of a storage device. This is particularly relevant for magnetic storage devices, such as hard drives and magnetic tapes. The strong magnetic fields disrupt the magnetic alignment of the storage particles on the media, effectively erasing the data stored on it. Degaussing is frequently employed as a method for data sanitization and secure data disposal, ensuring that sensitive information cannot be recovered.

The other options do not relate directly to the effects of strong magnetic fields on data storage media. Data mining refers to the process of analyzing large datasets to identify patterns or extract valuable information, not influenced by magnetic fields. Defense in depth is a security strategy that employs multiple layers of defense mechanisms to protect data, but it does not directly involve physical manipulation of data storage media. Database Activity Monitoring relates to tracking and analyzing actions taken within a database to enhance security and compliance, which isn't affected by magnetic fields.