Can someone give this answer?

How does frost use ambiguity to present his message about walls and neighbours what evidence supports the idea that the speaker believes good fences make good neighbors what details suggest the opposite

Which sentence from the article best supports the statement above

Why was west berlin in rubble "four decades ago"? a. that part of germany had been bombed during world war ii. b. reagan misspoke, as berlin was not in rubble 40 years ago. c. west berlin's highways were under construction.