Which one of the following shows optical activity?

How many chiral carbon atoms are present in the following compound?

$A$ compound contains $3$ chiral carbons. What is the number of possible optical isomers for this compound?

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

The correct statement$(s)$ about the compound $H_3C-CH(OH)-CH=CH-CH(OH)-CH_3$ $(X)$ 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 $2$.

Which of the following molecules can rotate the plane of plane-polarized light?