To provide firewall traversal, which components are needed?

A.
2 CiscoTelePresenceVideo Communication Server Expressways

B.
1 CiscoTelePresenceVideo Communication Server Control and 1 Cisco
TelePresenceVideo Communication Server Expressway

C.
2 CiscoTelePresenceVideo Communication Server Controls

D.
1 CiscoTelePresenceVideo Communication Server Control and 2 CiscoTelePresence
Video Communication Server Expressways