When using the SIP protocol, you need to use the local digit map for matching. If the default matching mode is used to match the 7-digit number starting with 7727, then the following options can be?
A . Local-digit map add huawei normal 7727xxx/7726.
B . Local-digit map add huawei normal 772./7727xxx
C . Local-digit map add huawei normal 7727
D . Local-digit map add huawei normal 7727xxx/7727
Answer: D