Question

(2R,3R)-2,3-Dibromobutane: Which of the following will have the same energy after undergoing ring flip?
a) (2S,3S)-2,3-Dibromobutane
b) (2R,3S)-2,3-Dibromobutane
c) (2S,3R)-2,3-Dibromobutane
d) (2S,3R)-3,2-Dibromobutane