A marketer is completing a Send Preview based on a pre-deployment checklist.
What task is validated during the Send Preview?

The email marketing manager at Northern Trail Outfitters would like to build a new audience that will combine unique subscribers who are in their Tent Purchasers data extension and their Tent Browsers data extension.
How should this new audience be created?

A marketer needs a quick count of record in a data extension with 'Djibouti' as they value for Country.
What should they use to determine the number of matching records in the least amount of steps?

NTO has the list of platinum members containing 50 thousand subscribers, and a lifetime member list, containing 20 thousand subscribers, 7 thousand subscribers in the lifetime member list also exist in the platinum member list, an email is being deployed to the platinum member but marketing team would now like to send the same email to the lifetime member list what feature should be use when sending the 2nd email to ensure that the7 thousand subscribers that exist on both list don't receive the same mail twice

Northern Trail Outfitters wants to ensure that the Email Address field value is not duplicated in a data extension.
What should a marketer do to ensure the Email Address field values are unique?