In addition to real-time protection, scheduled antivirus scans help ensure:

• A. Regular updates to the operating system.
• B. Verification of antivirus functionality by scanning with a test file.
• C. Consistent detection of dormant or unknown threats.
• D. Regularly scanning the system to detect threats that real-time protection may miss.

Answer: (D)

Real-time protection guards you as files are opened or executed, but it isn’t perfect. Some threats can stay dormant, hide in archives, or arrive in ways that slip past active monitoring. Scheduled antivirus scans provide a thorough, periodic sweep of the whole system using current definitions and heuristics. By scanning all files, folders, and compressed archives, the scan can uncover malware that didn’t trigger or was missed during normal protection. This layered approach helps maintain security over time and catches threats that real-time protection may miss. Other options don’t fit as well: OS updates aren’t driven by scans alone, a test-file check is a one-off diagnostic, and while scans do help detect dormant threats, their primary purpose is the regular, comprehensive review of the system.