Which is a valid Cisco CRS 4.0 deployment scenario? （）

• A、redundant Cisco CRS Engines and a simplex database server  
• B、redundant Cisco CRS Engines with five simplex VoIP monitoring servers  
• C、redundant Cisco CRS Engines and databases running on two different nodes outside of the Cisco CRS cluster  
• D、redundant Cisco CRS Engines and databases with two VoIP monitoring servers and three recording servers