Your help desk staff are using the Longest idle setting in their call queue todetermine which agent receives the next call to the queue. One of your agents usesSkype for Business and can communicate with others users and make calls, butthey're not receiving any calls from the call queue. What is the cause?A$.$ The user needs to update their Skype client.B$.$ The user needs an additional license.C$.$ Longest idle doesn't work with Skype for Business.D$.$ Call queues don't work with Skype for Business.