<span>A.
The speaker thinks playfully about the wall; the neighbor respects the wall's authority.</span>
There are so many possible answers to this question... I think it's whatever you believe is holding you back.
The answer to this is blank, the question is not here.
What to produce
One in which marginal coast are greater than marginal benefits
You have to give part of the page you think the answer will be on or the whole page