Refer to the exhibit.

Which CSS is used at the HQ Cisco Unified Communications Manager to reroute calls via the PSTN
when the SAF network is unavailable?

A.
the phone device CSS

B.
the phone line CSS

C.
the phone line/device combined CSS

D.
the SAF CSS configured on the CCD requesting service

E.
the phone AAR CSS configured at the phone device

F.
No special CSS is required. If SAF patterns are accessible, the PSTN reroute is automatic.