Which of the following reagents can react with both aldehydes and ketones?

Identify $A$ and $B$ from the following reactions:
$(I)$ $CH_3-CH=CH-CH_3 \xrightarrow{\text{(i) } O_3}{\text{(ii) } Zn-H_2O} 2X$
$(II)$ $2X$ $\xrightarrow[2. \Delta]{1. NaOH \text{ (dil.)}} Z$ $\xrightarrow[\text{(ii) } Zn-H_2O]{\text{(i) } O_3} A + B$

Reaction of a carbonyl compound with one of the following reagents involves nucleophilic addition followed by elimination of water. The reagent is

Ethylene is converted to $X$ on passing through a mixture of an acidified aqueous solution of palladium chloride and cupric chloride. Which of the following reagents readily take part in addition reaction with $X$?

Write a note on the addition of sodium hydrogen sulphite $(NaHSO_3)$ to the carbonyl group.

An organic compound $A$ reacts with methyl magnesium iodide to form an addition product,which on hydrolysis gives compound $B$. Compound $B$ gives a blue color in the Victor Meyer test. What are compounds $A$ and $B$ respectively?