XDR Custom Detection Rules Documentation): In Microsoft Defender XDR, custom detection rules are scheduled KQL queries that evaluate telemetry on a recurring schedule, using a lookback (loopback) period to determine how much historical data to analyze during each run. The loopback period determines the time window over which data i s evaluated (e.g., 12 hours, 48 hours). To change this period, administrators modify the rule's schedule configuration - specifically the frequency or recurrence settings in the custom detection rule editor. The KQL query (including summarize or where oper ators) defines the logic but not the temporal scope of data evaluation. Therefore, extending the loopback from 12 hours to 48 hours requires adjusting the frequency (schedule) configuration of the rule, not the query itself. # Correct Answer: A. the freque ncy