Which digital voice circuit supports 23 voice (B) channels and signaling that is earned in a dedicated 64 kb/s data (D) channel?

Which digital voice circuit supports 23 voice (B) channels and signaling that is earned in a dedicated 64 kb/s data (D) channel?

A.
E1-CAS

B.
T1-CAS

C.
E1-PRI

D.
T1-PRI

Explanation: