You are the Office 365 administrator for your company. The company allows external communications through Microsoft Lync Online for all domains.
The call center manager reports that call center personnel are spending too much time chatting with friends and not enough time taking calls. She requests that the
call center personnel be blocked from chatting with anyone external to the company by using Lync Online. They still must be able to communicate with internal
users.
You need to prevent all call center personnel from communicating with external contacts by using Lync Online, while still allowing other employees to communicate
with external contacts.
What should you do?

A.
In the Lync admin center, select all users, edit their external communications settings, and clear the Lync Users check box.

B.
On the External Communications page of the Lync admin center, turn off external access.

C.
In the Lync admin center, remove the Lync Online license from each of the call center personnel.

D.
In the Lync admin center, select all call center personnel, edit their external communications settings, and clear the People on Public IM Networks check box.