Which of the following compounds on reaction with ammoniacal silver nitrate solution forms a precipitate of silver?

Arrange these compounds in decreasing order of reactivity for the nucleophilic addition reaction :
$I.$ Acid chloride $II.$ Aldehyde
$III.$ Ketone $IV.$ Ester
Select the correct answer from the codes given below :

Methyl vinyl ketone on reaction with $LiCuMe_2$ gives a major product,whose structure is

What product is formed when benzaldehyde reacts with methylamine?

The structure of $A$ in the given reaction is:

Which of the following compounds reacts with ammonia to form urotropine?