What can you use in a centralized call processing environment to dynamically reroute a call over PSTN if the call exceeds the allocated WAN bandwidth?

A.
PSTN Automated Failover (PAF)

B.
WAN Redirection Algorithm (WRA)

C.
Automatic WAN Provisioning (AWP)

D.
Automated Alternate Routing (AAR)

Explanation:
Cisco CallManager System Guide, Release 4.0(1)
Understanding Route Plans
Automated Alternate Routing
Automated alternate routing (AAR) provides a mechanism to reroute calls through the PSTN or other network by using an alternate number. As a subset of the AAR feature, Cisco CallManager automatically reroutes calls through the PSTN or other networks when Cisco CallManager blocks a call due to insufficient location bandwidth. With automated alternate routing, the caller does not need to hang up and redial the called party.
http://www.cisco.com/en/US/partner/products/sw/voicesw/ps556/products_administration_guide_chapter09186 a