Which one of the following compounds will give dimethyl glyoxal with $SeO_2$?

$CaOCl_2 + H_2O \longrightarrow Ca(OH)_2 + X$
$X + CH_3CHO \longrightarrow Y$
$Y + Ca(OH)_2 \longrightarrow CHCl_3$
What is '$Y$'?

Phenylmagnesium bromide,upon reaction with a compound $X$ followed by treatment with acid,gives benzyl alcohol. The compound $X$ is

The reaction of $5-$methylenecyclohex$-2-$enone with $2$ equivalents of $HBr$ yields which of the following products?

This conversion can be achieved by

$P$ is an optically active compound with molecular formula $C_6H_{12}O$. When $P$ is treated with $2,4-$dinitrophenylhydrazine,it gives a positive test. However,in the presence of Tollens reagent,$P$ gives a negative test. Predict the structure of $P$.