Which of the following compounds,upon hydrolysis followed by heating,gives a product that yields a positive iodoform test?

In the following sequence of reactions,the final product $D$ is:

Reduction of aldehydes and ketones to hydrocarbons takes place in the presence of:

The ratio $x / y$ on completion of the above reaction is $.........$.

An organic compound $(X)$ with molecular formula $C_3H_6O$ is not readily oxidised. On reduction it gives $(C_3H_8O)$ $(Y)$ which reacts with $HBr$ to give a bromide $(Z)$ which is converted to a Grignard reagent. This Grignard reagent on reaction with $(X)$ followed by hydrolysis gives $2,3-$dimethylbutan$-2-$ol. Compounds $(X)$,$(Y)$ and $(Z)$ respectively are $:$

Which is the best oxidizing agent to oxidize $CH_3CH=CHCHO$ to $CH_3CH=CHCOOH$?