You need to recommend changes to the proposed Lync server design to meet the companys availability requirements for voice mail. What should you include in the recommendation?

A.
two call attendants

B.
two Location Information Servers

C.
two Response Groups

D.
an additional server that has the Unified Messaging server role deployed

Explanation:
[!] Need full case info, but RGs and CAs are logical components that will failover to available hosts, and LIS is not used for voicemail. If the only UM server fails, no voicemail for anyone.