Computer Science - Networking - Discussion

I think the ans is A.Could anyone specify the correct answer.

B. The address is made up of the international data number (IDN), which consists of two fields: the 4 digit data network identification code (DNIC) and the (up to) 10 digit national terminal number (NTN).

The DNIC has three digits to identify the country (one to identify a zone and two to identify the country within the zone) and one to identify the PDN (allowing only ten in each country).

The first four digits of the international data number (IDN) is same as Network User Address on this question?

Can anyone confirm this?

Can anyone give the total explanation of NUA CODE means which segment of digits represents what?

The first 4 digits are known as the DNIC, which identifies the particular network. The remaining digits are then assigned at the discretion of the network operator - for example, in the UK, the BT PSS network of the 1980s employed a numbering system using a 3-digit area code (which conformed with the area code of the telephone network) plus a 5-digit subscriber number, and another 2 digits were available for the sub-address.

Means there are total 14 digits out of which

DATA NETWORK IDENTIFICATION CIDE (1-4).
AREA CODE (5-7).
TERMINAL NUMBER (8-12).
SUB ADDRESS (13-14).