The correct answer is B. UserCheck . In SmartConsole, Custom Policy Tools are used to manage Threat Prevention policy objects and tuning components such as profiles, IPS protections, indicators, and protection categories. The official R81.20 guide shows Custom Policy Tools > Profiles for profile creation, editing, and cloning, and Custom Policy Tools > IPS Protections for managing IPS protection behavior. The same guide also shows Custom Policy Tools > Indicators as the location used to configure external IoC feeds.
Malicious Activity Detection is represented through Threat Prevention protection types: the Protections Browser displays protection types, and the guide states that Malicious Activity and Unusual Activity protection types contain lists of protections. UserCheck, however, is not itself a Custom Policy Tools setting.
It is a user interaction and notification mechanism configured inside relevant blade/profile settings, such as Anti-Bot or Zero Phishing UserCheck messages. Therefore, among the choices, UserCheck is the item that does not belong as an available Custom Policy Tools setting. Reference topics: Custom Policy Tools, IPS Protections, Indicators, Threat Prevention Profiles, Protections Browser, UserCheck settings.