What type of threat does ransomware represent?

Ransomware is classified as a specific type of malware that targets computer systems by encrypting files, rendering them inaccessible to the victim. The malicious actor behind the ransomware then demands payment, frequently in cryptocurrency, in exchange for the decryption key that would restore access to the victim's own data. This distinct characteristic of encryption and a ransom demand is what sets ransomware apart from other types of malware or attacks.

While option A refers to malware that destroys data, ransomware typically does not destroy data outright but rather restricts access to it by encrypting it. Option B describes phishing attempts, which are primarily aimed at tricking individuals into revealing personal information, and do not involve file encryption or ransom. Option D relates to social engineering attacks, which may manipulate individuals into giving away confidential information, but it does not involve the technical mechanisms of file encryption or monetization through ransom, which are central to ransomware attacks. Therefore, the choice that accurately defines what ransomware represents is the one focused on its encryption of files and the ransom note demanding payment for their release.