Which feature does Windows Defender include for enhanced system security?

Windows Defender includes real-time protection as a critical feature that significantly enhances system security. This functionality continuously monitors the system for potential threats and malware, scanning files and applications as they are accessed or executed. By actively scanning and blocking malicious software in real-time, Windows Defender helps prevent infections before they can cause harm, thereby maintaining the integrity and security of the user's system.

Real-time protection is essential because cyber threats are often designed to evade detection and can exploit system vulnerabilities rapidly. By utilizing this feature, users can ensure their devices are consistently shielded from known and emerging threats, allowing for a proactive approach to cybersecurity.

The other options, while beneficial in various contexts, do not directly contribute to the core security features provided by Windows Defender. For example, cloud storage integration relates to data accessibility rather than immediate system defense, a free VPN service focuses on privacy and internet security rather than system security, and a system performance optimizer improves device efficiency rather than providing protective measures against threats.