Which feature must also be enabled to prevent these attacks?

A customer is seeing an increase in the number of malicious files coming in from undetectable sources in their network. These files include doc and .pdf file types.

The customer uses a firewall with User-ID enabled

Which feature must also be enabled to prevent these attacks?
A . Content Filtering
B . WildFire
C . Custom App-ID rules
D . App-ID

Answer: B