The Acme Roller Skates Company has its corporate HQ in Seattle, with remote sales offices in Denver, Chicago, New York, and Atlanta. The company is in the process of transitioning the H.320 videoconferencing system to an IP videoconferencing system. The company has installed an MCU at the corporate HQ, but the remote offices still have 320 terminal endpoints. A Cisco IPVC 3526 PRI Videoconferencing Gateway has been installed to allow the remote offices to dial into videoconferences. The telephony provider has given the company a block of 100 phone numbers for the PRI, which can route to all the channels on the PRI. Which method will be best for routing calls from the gateway to the MCU or other endpoints?

A.
TCS4

B.
DID

C.
Default Extension

D.
IVR