Comprehensive and Detailed Explanation From Exact Extract:
FromNokia 7750 SR OS OSPF Guide - Interface Types and ABR Configuration Section:
"When configuring ABRs and multiple OSPF areas, it's critical that the area numbers are assigned correctly, and point-to-point interfaces are configured where appropriate to eliminate DR/BDR elections on serial or direct links." Analysis:
From topology:
R3 connects Area 0 (to R4) and Area 1 (to R2) # R3 is an ABR.
The correct configuration must:
Assign proper areas for each link.
Use point-to-point on R3's interface to R4 to avoid unnecessary DR/BDR election.
Option A is incorrect - missing interface-type point-to-point on R3's "toR4" link.
Option B is correct - properly configuresinterface-type point-to-pointon R3's Area 0 interface toward R4.
Option C & D - either configure unnecessary point-to-point everywhere or misplace interface-type statements.
Thus, per Nokia OSPF ABR configuration standards, the correct answer is B.
#Fully verified using official Nokia 7750 SR OS OSPF documentation (interface-type configuration, ABR behavior, and protocol encapsulation standards).