To provide firewall traversal, which components are needed?

A.
1 Cisco TelePresence Video Communication Server Control and 2 Cisco TelePresence
Video Communication Server Expressways

B.
2 Cisco TelePresence Video Communication Server Expressways

C.
1 Cisco TelePresence Video Communication Server Control and 1 Cisco TelePresence
Video Communication Server Expressway

D.
2 Cisco TelePresence Video Communication Server Controls