Explanation: The option that accurately defines the capabilities of a segmentation rule is that segmentation rules are used to segment prospects based on their activities and demographic data. A segmentation rule is a type of rule that allows marketers to segment their prospects based on specific criteria, such as field values, activities, or scores. A segmentation rule can be used to create dynamic lists, add prospects to campaigns, or apply tags or completion actions. Segmentation rules are not used to create new forms, score and grade prospects, or assign prospects to users in Salesforce, as these are different functions that require different tools.