The number of all the possible stereoisomers formed by the given compound is

Identify which of the structures below are meso structures ?

The structure of $(S)-2$ -fluorobutane is best represented by

Which of the following is a meso compound ?

The correct statement$(s)$ about the compound $\mathrm{H}_3 \mathrm{C}(\mathrm{HO}) \mathrm{HC}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH}(\mathrm{OH}) \mathrm{CH}_3(\mathbf{X})$ is(are)

$(A)$ The total number of stereoisomers possible for ${X}$ is $6$

$(B)$ The total number of diastereomers possible for ${X}$ is $3$

$(C)$ If the stereochemistry about the double bond in ${X}$ is trans, the number of enantiomers possible for ${X}$ is $4$

$(D)$ If the stereochemistry about the double bond in ${X}$ is cis, the number of enantiomers possible for ${X}$ is $2$

$2$-chlorobutane $+\mathrm{Cl}_2 \rightarrow \mathrm{C}_4 \mathrm{H}_8 \mathrm{Cl}_2$ (isomers)

Total number of optically active isomers shown by $\mathrm{C}_4 \mathrm{H}_8 \mathrm{Cl}_2$, obtained in the above reaction is......................