Send Logging, once enabled, writes granular, per-send detail — including the exact email address and content used for each individual message — into a dedicated Send Log Data Extension that marketers can directly query for troubleshooting purposes such as verifying which address received which content on a specific send. Because the scenario explicitly states the Send Log is already being populated and is growing in size, the natural and correct recommendation is to query that existing Send Log Data Extension directly via SQL rather than standing up an entirely separate reporting mechanism. Option A, a Filter Activity on the Sendable Data Extension, only reflects current-state subscriber data, not the historical, point-in-time send detail needed to troubleshoot a specific past send. Option B, Tracking Extracts, capture engagement and delivery-status events rather than the detailed content/address-level send record that Send Logging specifically provides — it answers a different question (did it send/open/bounce) rather than ' which exact address and content combination went out. ' Option D, Sent and Subscriber Data Views, reflect general send and current subscriber status but similarly lack the granular per-send content-and-address audit trail that Send Logging is uniquely designed to preserve. Reference: Send Logging, SendLog Data Extension.

Journey Builder performs best when the heavy lifting of segmentation happens before contacts are evaluated for entry, not inside the journey itself. Performing large-scale segmentation in Automation Studio (B) offloads CPU-intensive filtering to SQL Query Activities, which are optimized for bulk processing across millions of rows, rather than relying on Journey Builder ' s per-contact entry evaluation engine. Creating a prefiltered, dedicated sendable copy of the source data extension for each journey (D) avoids lock contention and re-evaluation overhead that occurs when multiple journeys share a single large entry source, and it ensures each journey only processes the exact population it needs. Option A is a valid best practice for decision-split performance generally, but Attribute Groups govern contact-level data joins for Contact Data-based splits and does not address entry-source scale at 10 million records specifically — it ' s a secondary optimization, not one of the two primary levers for this scenario. Option C describes filtering directly on the entry source Data Extension, which still forces Journey Builder to evaluate the full underlying population against the filter at entry time, rather than pre-segmenting it, and is less efficient than doing that work in Automation Studio beforehand. Reference: Journey Builder Performance Best Practices, Automation Studio Segmentation.

The Contact Data View is the authoritative system data view that reflects the full Contact model in Marketing Cloud, including all contacts synchronized from connected Salesforce orgs and those created natively. A scheduled Automation Studio sequence — SQL Query Activity against the Contact Data View, followed by a Data Extract Activity configured to email the resulting file or a notification — satisfies a recurring, hands-off weekly report to the CMO. Option C is close in mechanics but targets the Subscriber Data View, which reflects the legacy All Subscribers list rather than the full Contact model; in a Contact Model-enabled account, this undercounts or misrepresents the true contact base. Option A references a ' Contact Extract Activity, ' which is not a standard Automation Studio activity name — Data Extract Activity is the correct term, and it operates on Data Extensions, not directly on a live count without a preceding query. Option B ' s ' Contacts Counts Standard Report ' is not an out-of-the-box Marketing Cloud report. Consultants should default to querying the correct data view for the object being counted, then automating the export/notification with Automation Studio rather than relying on manufactured report names. Reference: Marketing Cloud Data Views, Automation Studio Query and Extract Activities.