Read the following excerpt from the poem "mending wall" by robert frost: there where it is we do not need the wall: he is all pine and i am apple orchard. my apple trees will never get across and eat the cones under his pines, i tell him. he only says, 'good fences make good neighbors.'

which best describes the effect of the metaphor on the overall meaning in this excerpt?

a. it describes the difference between the bordering properties to underscore the necessity of the wall.
b. it gives apple trees the qualities of grazing animals to emphasize that the wall is unnecessary.
c. it attributes human qualities to the wall in order to echo the idea of apple trees being livestock.
d. it compares two unlike things that are harmful to humans to show that the wall is necessary.