When must a service define entity rules?

[Reference: https://docs.splunk.com/Documentation/ITSI/4.10.2/SI/EntityRules, A is the correct answer because a service must define entity rules if the intention is for the KPIs in the service to filter to only entities assigned to the service. Entity rules are filters that match entities to services based on entity aliases or entity metadata. If you enable the Filter to Entities in Service option for a KPI, you need to define entity rules for the service to ensure that the KPI search results only include the relevant entities for the service. Otherwise, the KPI search results might include entities that are not part of the service or exclude entities that are part of the service. References: [Define entities for a service in ITSI], [Configure KPI settings in ITSI]]