. Consider the following reaction profiles where A reacts with reagent R

and gets converted to C, and B reacts with the same reagent R under identical conditions and gets converted to D. Compounds A and B are stereoisomers of each other, and compounds C and D are also stereoisomers of each other.

Which statement about these compounds must be true

A. A and B are E and Z isomers respectively

B. A and B are diastereomers

C. C and D are meso compounds

D. C and D are constitutional isomers