For the customer's needs involving Smart Capture forms, cross-referencing event registration data with email activities, and triggering follow-up emails based on specific actions (like clicking but not completing registration), SQL skills are essential. SQL would be used to query the data extensions to identify which customers clicked the registration link but did not complete the registration form. This information can then be used to target follow-up communications effectively.
Reference: Salesforce Help - SQL Query Activity

To manage data retention for inactive data in data extensions, the best approach is to apply a Row Based Retention policy directly to each data extension. This method allows precise control over how long data is retained based on the creation or modification date of each row.
Row Based Retention: Set this on each data extension as it is configured. Specify that data should be cleared after 12 months of inactivity. This approach ensures that only data which has not been engaged with for the specified period is removed, thus optimizing data storage and maintaining compliance with data management policies.
Reference: https://help.salesforce.com/

To verify if a test email has been sent from Email Studio, the admin should:
Navigate to Email Studio.
Go to the My Tracking tab.
Select Test Send Emails. This section provides a detailed log of all test emails sent, including their status and timestamp, allowing the admin to confirm whether the test email was deployed successfully.
Reference: Salesforce Marketing Cloud Email Studio Documentation

To configure a journey using Path Optimizer with a holdback of 60% of the contacts until a winner has been selected, the Marketing Cloud admin needs to set:
A). Data Extension entry source: Ensures the journey is pulling contacts from a specific data extension which can be effectively managed and monitored for the experiment.
D). Winner evaluation: This setting allows the admin to specify how and when the winning path is determined, which is critical to managing the holdback and subsequent path optimization.
Reference: Salesforce Help - Path Optimizer

When considering a Dedicated IP for global marketing efforts, Northern Trail Outfitters should consider:
Stack alignment: Ensure all accounts are on the same stack to facilitate shared use of the Dedicated IP across different geographical locations.
Send volume: A dedicated IP is beneficial if the send volume is significant enough to maintain and build a positive sender reputation. Regular, consistent high-volume sending is crucial for IP warming and reputation.
Reference: Salesforce Marketing Cloud Sender Authentication Package Documentation