When an incoming PSTN call arrives at an MGCP gateway, how does the called number get normalized to an internal directory number in Cisco Unified Communications Manager?

When an incoming PSTN call arrives at an MGCP gateway, how does the called number get normalized to an internal directory number in Cisco Unified Communications Manager?

A.
Normalization is done by configuring the significant digits for inbound calls on the MGCP gateway.

B.
Normalization is done using route patterns.

C.
Normalization is done using the gateway incoming called party prefixes based on number type.

D.
Normalization is done using the gateway incoming calling party prefixes based on number type.

E.
Normalization is achieved by local route group that is assigned to the MGCP gateway.

Explanation: