Total number of optically active compounds from the following is. . . . . . 

Which of the following is a meso compound ?

Rotation of plane polarised light is measured by

Total number of compounds with Chiral carbon atoms from following is___________.   $IMAGE$

$ \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}\left(\mathrm{NO}_2\right)-\mathrm{COOH} $

$ \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CHBr}-\mathrm{CH}_2-\mathrm{CH}_3 $

$ \mathrm{CH}_3-\mathrm{CH}(\mathrm{I})-\mathrm{CH}_2-\mathrm{NO}_2 $

$ \mathrm{CH}_3-\mathrm{CH}_2-\mathrm{CH}(\mathrm{OH})-\mathrm{CH}_2 \mathrm{OH} $

$ \mathrm{CH}_3-\mathrm{CH}-\mathrm{CH}(\mathrm{I})-\mathrm{C}_2 \mathrm{H}_5 $

Among the following, $L-$ serine is

The number of stereoisomers possible for a compound of the molecular formula

$CH_3 -CH = CH -CH( OH)-Me$ is :