Which of the following best defines ransomware?

Ransomware is best defined as malicious software that encrypts data, preventing access to it until a ransom is paid to the attacker. This type of malware targets individuals and organizations, often using social engineering techniques to gain access to systems. Once it infiltrates a system, it encrypts files or entire drives, effectively locking users out of their own data. The attackers then demand payment—typically in cryptocurrency—to provide the decryption key needed to regain access to the files.

The other choices describe different types of software and do not relate to the nature or function of ransomware. For instance, software that improves system performance enhances the efficiency of a computer system rather than causing harm. Data recovery software focuses on restoring lost or corrupted data, which is contrary to the purpose of ransomware. Finally, network monitoring software is designed to oversee and manage network traffic, looking for issues and performance optimization rather than accessing or encrypting data. Thus, the defining characteristic of ransomware being malicious software that encrypts data makes it stand apart from other software categories.