See networking. Assume that all terminals have been registered to GK/SC, there are no port restrictions on NAT1 and NAT2, and all terminals are TE30 terminals (H.323). Then T1 calls T3. Which of the following description is correct?

See networking. Assume that all terminals have been registered to GK/SC, there are no port restrictions on NAT1 and NAT2, and all terminals are TE30 terminals (H.323). Then T1 calls T3. Which of the following description is correct?
A . GK routing is required
B . Unable to communicate with each other
C . Can communicate directly with each other
D . Requires MCU routing

Answer: C