Final answer:
In an organization, when associating an entitlement with a case record, the entitlement lookup field displays only the active entitlements associated with the case customer.
Step-by-step explanation:
When configuring an organization to use entitlements in a customer service context and associating an entitlement with a case record, the option displayed in the entitlement lookup field on the case record is A. only active entitlements associated with the case customer. These entitlements are what the customer is eligible for in terms of service or support, based on the products or services they have purchased or are subscribed to. This lookup helps to ensure that the support team is aware of the specific service level agreed with the customer for a particular case.