What are two reasons to include the email address when importing a list of contacts? (Choose two.)

A query on recipients is added to a workflow. The query needs to be able to obtain the last three transactions for each recipient.
Which method should be used to obtain this result?

A workflow is paused and an activity is blinking with a red halo. How can a business practitioner determine what the error is for this activity?

How should a campaign business practitioner send a proof to a seed list?

A query returns 0 records for a specific date. What is the most efficient method to determine what dates exist in the table?