Which statement is true about deploying WebEx OneTouch?

Which statement is true about deploying WebEx OneTouch?

A.
WebEx-enabled meetings do not use ports in the CTMS.

B.
The WebEx plug-in is not used for WebEx OneTouch scheduling.

C.
Outbound TCP 443 SSL connections are not able to pass through the system firewall.

D.
WebEx OneTouch supports a proxy server.