An Cisco Unified Contact Center Express 4.0 deployment requires support for 20 concurrently logged-in agents. The agents are split across two remote sites, and the high-availability Cisco CRS Engine, Database Server, VoIP Monitoring, and Recording server processes run at a central data center. The agents will be using CAD with Cisco Unified IP Phone 7960G and end-point monitoring. Very little recording and silent monitoring will be performed, and no historical reporting will be done during call center open hours. Assume the minimum number of servers is desired.   How many Cisco Unified Contact Center Express hardware servers would be required for this Cisco Unified Contact Center Express deployment?（　） 

• A、1  
• B、2  
• C、3  
• D、4  
• E、5