Which of the following best describes cyberespionage?

Cyberespionage is best defined as covert activities aimed at obtaining secret information, typically for strategic or political purposes. This practice involves stealthy methods to infiltrate networks and gather sensitive data without the knowledge of the target. It often includes accessing governmental, corporate, or individual data that is not publicly available and is usually protected by various security measures.

The notion of "covert activities" underscores the secretive nature of cyberespionage, distinguishing it from more overt intelligence-gathering efforts. This practice is often employed by nation-states or organizations seeking to gain an advantage, whether in political, economic, or military terms.

The other choices, while related to aspects of cybersecurity and information gathering, do not encapsulate the essence of cyberespionage. Military operations, publicly available intelligence, and legal investigations all have distinct purposes and methods that differ from the clandestine and strategic nature of cyberespionage.