Which feature must be configured before an administrator can use the outbreak filter for nonviral...

The feature that must be configured before an administrator can use the outbreak filter for nonviral threats is antispam. The outbreak filter relies on the antispam engine to detect and block nonviral threats, such as phishing, malware, or spam campaigns. You need to enable antispam scanning and configure the antispam settings before you can use the outbreak filter.

References: Securing Email with Cisco Email Security Appliance (SESA) v3.1, Module 8: Using Anti-Virus and Outbreak Filters, Lesson 2: Configuring Outbreak Filters