Universal Containers has millions of customers in Salesforce, but only a very small percentage have opened support cases in the past. Recently, Universal Containers has implemented a Service Cloud portal and plans to allow customers to be authenticated users to increase self-service rates. Which method should be used to enable the customers on the portal? (Choose 2) A. Have agents manually create users when portal access is requested by customers. B. Identify active customers and send them registration instructions via email. C. Create active customers as portal users and send them email notifications D. Have agents provide customers with portal registration instructions when working on a case