Chemistry - STEREO ISOMERISM Question with Solution | TestHub

Definition: Diastereomers are stereoisomers that are not mirror images of each other, meaning they differ in configuration at some (but not all) chiral centers.

Analysis: All five options represent 3-bromobutan-2-ol, which contains two distinct chiral carbons ($C_2$ and $C_3$).

Comparison: Converting the Newman projection (b) into a wedge-dash format and finding the $R/S$ configurations reveals that (a) and (b) share one identical chiral center configuration while the other is inverted.

Conclusion: Because they are non-mirror image stereoisomers, (a) and (b) are diastereomers, making (D) the correct option.