Access to the Service Console and other advanced Service Cloud features (like Entitlements or Knowledge) requires a specific Feature License called the Service Cloud User. Even if a user's profile has the "Manage Cases" permission, they will not be able to access the specialized Console app unless the "Service Cloud User" checkbox is selected on their individual User record. This is a common administrative step when onboarding new support staff. Permission sets (Option B) grant functional permissions but cannot grant feature licenses. Assigning a "Platform User License" (Option D) would actually restrict them, as that license type does not include access to standard CRM objects like Cases or the Service Console.