The correct option is
A highlight his feeling that he is different from others in the community.
The correct answer is option A. Cecil brings up fences to illustrate more fully the point he begins making, when he refers to “irremovable barriers” between himself and the rest of the community; this supports the idea that he feels he is different from the others.
Although Cecil finds aspects of polite society frustrating, he does not feel excluded from that society; in fact, some of his frustrations stem from being considered a part of it. Thus, option B is incorrect.
Cecil does express a desire for privacy, but he also says that he “must accept” the differences between him and other members of the community, indicating that he does not plan to demand privacy; he also does not express a desire for a secluded house, merely for the privacy of his relationship with Lucy. Option C is therefore incorrect.
As he talks about fences, Cecil is clarifying for Lucy’s benefit something he has thought about previously, not sharing a sudden revelation; thus, option D is incorrect.