C. An apple orchard. This is the correct version.
" 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." The poet thinks the wall is useless between these two pieces of lot. If the neighbour's pines get into the poet's lot, he will just eat the pine's fruits. He does not see any problem, and he thinks his apples will never get into the neighbour's lot.
These options are wrong:
A. A pine forest. The narrator's neighbour has pine trees.
B. A cow farm . There are not cows in the area. As there are not cows, the narrator thinks the wall is useless.
D. A rabbit nursery . There are rabbits in the whole area.