Which Cisco CRS 4.0 server configuration task enables the Cisco CRS server to fail over to a secondary Cisco Unified CallManager when the primary Cisco Unified CallManager fails?（）

• A、The LDAP directory must have a secondary profile configured.  
• B、No special configuration is required. Cisco Unified CallManager maintains the failover.  
• C、The JTAPI provider on the Cisco CRS server must be configured with the secondary Cisco Unified CallManager IP address following the primary Cisco Unified CallManager IP address.  
• D、There must be a second JTAPI user configured with an alternate range of CTI ports.