To ensure email campaigns are sent successfully, what attribute must be marked in a data extension?

When setting up email campaigns in Salesforce Marketing Cloud, the attribute that plays a crucial role in determining whether a data extension can be used for sending emails is "Is Sendable." This attribute must be marked to indicate that the records within that data extension are eligible recipients of email campaigns.

By marking a data extension as sendable, it ensures that the necessary fields, such as email addresses, are available and correctly formatted for the delivery of emails. This allows the system to recognize the data extension's readiness for email sends, facilitating a smooth campaign execution. A data extension that is not marked as sendable will not be included in any email sends, thereby potentially hindering the campaign's reach and effectiveness.

The other attributes, while relevant in different contexts, do not address the core requirement for enabling an email data extension to be utilized in campaigns. For instance, "Is Active" pertains to the state of the data extension itself rather than its usability for sends, while "Is Unique" focuses on record uniqueness and "Is Confirmed" might relate to subscriber status but not specifically to sending capabilities.