Verification is the correct answer. A verification activity is an activity that allows you to set criteria for an automation to run successfully or fail based on data counts or validation errors. For example, you can use a verification activity to check if the number of records in a data extension is within a certain range before sending an email. This can help prevent sending emails to more subscribers than intended or to an empty data extension. You can learn more about this in the [Automation Studio Basics] module on Trailhead.