Three of the structures shown are meso compounds. Which one is NOT a meso compound?

(A) is (2R,3S)-2,3-dibromobutane, (B) is cis-1,3-dibromocyclohexane and (C) is (3R,4S)-hexane-3,4-diol. In each, the two stereocentres carry the same set of groups with opposite configurations, so an internal mirror plane exists and the compound is meso. (D) is (2S,3S)-2,3-dichlorobutane: both centres have the same descriptor, there is no mirror plane, and the compound is chiral (one enantiomer of the resolvable pair).