as SIP trunks?

A Cisco TelePresence solution is built based on SIP protocol. Which three links are configured

as SIP trunks? (Choose three.)

A.
CTS endpoint to CUCM

B.
CTMS to CUCM

C.
Cisco IP Phone 7975 or 7970 to CUCM

D.
CUCM to CUBE

E.
CTRS to CUCM