Refer to the exhibit.

The correct answer is C because the rule’s Group By attributes determine how events are grouped before the aggregate condition is evaluated. The Study Guide explains that rule conditions are built from subpatterns consisting of event attribute filters and aggregation functions. It also explains that a subpattern combines filters, aggregate, and group by fields to form the rule logic. In this case, the filters may return matching events in Analytics, but the rule still may not trigger because the aggregate condition is calculated separately for each unique Group By combination. The exhibit groups by Destination IP and User while applying COUNT(Source IP) > = 2. This means FortiSIEM does not count all matching events together. Instead, it counts only events that share the same Destination IP and User combination. If no single grouped combination reaches the aggregate threshold, no incident is created. The issue is not the event lookup, not the Destination Host Name format, and not necessarily the aggregate expression itself. The grouping logic is what restricts the counted event set.