How does the Anti-Virus feature of the Threat Prevention policy block traffic from infected websites?

How does the Anti-Virus feature of the Threat Prevention policy block traffic from infected websites?
A . By dropping traffic from websites identified through ThreatCloud Verification and URL Caching
B . By dropping traffic that is not proven to be from clean websites in the URL Filtering blade
C . By allowing traffic from websites that are known to run Antivirus Software on servers regularly
D . By matching logs against ThreatCloud information about the reputation of the website

Answer: D