A manual diagnostic session causes AppDynamics to collect detailed transaction snapshots for the selected Business Transaction during the active diagnostic period. When an instance of that Business Transaction crosses multiple instrumented tiers or nodes, the snapshot collection context is propagated with the transaction. Consequently, AppDynamics captures the participating transaction segments from all nodes through which the Business Transaction passes, producing an end-to-end distributed snapshot.

The capture is not restricted to transactions classified as slow, very slow, or errors. Those classifications are commonly used by automatic diagnostic-session and snapshot-triggering mechanisms, whereas a manual session is deliberately initiated to gather deeper diagnostic evidence, including transactions that might otherwise be considered normal.

Option D is incomplete because the triggering node initiates snapshot collection, but the resulting distributed snapshot can include downstream nodes that participate in the transaction. Options A and C incorrectly limit collection to performance-policy violations and error conditions.

Relevant CAAPA Study Guide topics include Transaction Snapshots, Manual Diagnostic Sessions, Distributed Transaction Correlation, Call Graph Collection, Business Transaction Health, and Cross-Tier Transaction Tracing.