B is the best answer among the available choices , because an Audience Flow with a Data 360 Segment source is the appropriate architecture for a dynamically changing audience. Salesforce states that Data 360 segments update membership based on profile attributes and behavioral data, while Audience Flows can use those segment members as their audience source.

For a "no purchase in 90 days" use case, the marketer defines the lapsed-customer criteria in a Data 360 segment. As purchase data changes and the segment republishes, qualifying customers enter or leave the segment automatically. The Audience Flow then orchestrates the scheduled re-engagement communication against the current membership.

An Automation Event-Triggered Flow is more appropriate for responding to discrete events, such as a form submission or email click. A Marketing Object stores marketing-specific tabular data and isn't a dynamic audience-management mechanism.

The uploaded bank keys B.

Technical precision: the Data 360 feature actually maintaining dynamic membership is the Segment ; Audience Flow is the orchestration layer consuming that segment. Because "Segment" isn't offered as an option, B is the only architecturally valid choice. Salesforce confirms both behaviors.

Study Guide Reference: Data Modeling, Identity Resolution and Segmentation → Dynamic Segments and Audience Flows.

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