Answer:
A) Walls can serve to keep things out as well as keep things in.
Explanation:
"Mending Wall" is a poem by Robert Frost (1874–1963). In this poem the speaker (or may be poet himself) wants his neighbor to consider some basic questions about walls i.e. are walls really needed? What is their purpose? What is their advantage and disadvantage? Interestingly the speaker or the poet does not give any conclusion. He asks question only so that his neighbor/reader just think about it and reach at some conclusion on their own just as Socrates used to ask questions from people and his students. The speaker’s neighbor initially answers that good wall make good neighbors because they remove confusions and clarify which area and property belongs to which neighbor. The speaker too agrees to this extent that walls may be a good way to include your property and exclude others. But what speaker is most concerned is the fact that we don’t usually consider which things we should include and which things we should exclude. Moreover we should always consider that our walls should not offend others.
These line start with a message that good wall make good neighbors by clearly marking which area and property belong to which group. The speaker says that since spring season has made him mischievous, he simply asks his neighbor, how do good walls make good neighbors? Aren't walls good only when there are cows, but there are no cows. The speaker agrees that walls are good to include and exclude things from your property, but speaker or any good person should consider that which things he has the right to wall in (include), and which things he should wall out (exclude from property). It seems the poet is trying to convey that walls also restrict sunshine, air and view to adjacent piece of land belonging to other person. So, one should consider such things and try to not offend other neighbors.
The basic theme of these lines is that walls can serve to keep things out as well as keep things in by walling in or walling out the things.
Second option is not correct because animals/cows are just used as one example of many things and this does not convey the wider theme of these lines.
Third and fourth options are not correct because the speaker questions the usefulness of walls and does not agree with his neighbor, nor does neighbor seem to agree with the speaker.
