2R,3S -butane-1,4-diol has two chiral centers: one at carbon 2 and another at carbon 3. There are four possible stereoisomers for this compound, which can be represented as follows:1. 2R,3S -butane-1,4-diol HO-CH2-CH 2R OH -CH 3S OH -CH2-OH2. 2S,3S -butane-1,4-diol HO-CH2-CH 2S OH -CH 3S OH -CH2-OH3. 2R,3R -butane-1,4-diol HO-CH2-CH 2R OH -CH 3R OH -CH2-OH4. 2S,3R -butane-1,4-diol HO-CH2-CH 2S OH -CH 3R OH -CH2-OHThese four stereoisomers are the possible combinations of the R and S configurations at the two chiral centers.