In the paragraph the author describes the body language displayed by people in certain situations. He begins by describing ‘small actions’ performed by ‘insulters’ and calls it ‘an exaggerated version of high status displays'. In the last line he describes how ordinary displays are for the dominant and the submissive. Since they are ordinary and not exaggerated, the difference between them is very subtle this is what option (a) is. Option (b) does the opposite. Options (c) and (d) seem to shift the focus of the discussion to other topics.