What field does the Subscriber Key become when considering under the relational database of Contact Builder?

True or False? Filtering subscribers or contacts makes targeting specific subscribers or contacts based on their attributes and other conditions easier.

Social Studio allows users to publish and review content, however it needs to be created in some external app.

Does the Marketing Cloud Architecture allow for Subscribers who do not have contacts?

True or False? When a data extension column is deleted, the system retains it as a soft delete.