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 :

The conversion of acetophenone into benzoic acid can be achieved by its reaction with

An optically active alkyl halide $C_4H_9Br$ $[A]$ reacts with hot $KOH$ dissolved in ethanol and forms alkene $[B]$ as the major product,which reacts with bromine to give dibromide $[C].$ The compound $[C]$ is converted into a gas $[D]$ upon reacting with alcoholic $NaNH_2.$ During hydration,$18 \ g$ of water is added to $1 \ mole$ of gas $[D]$ on warming with mercuric sulphate and dilute acid at $333 \ K$ to form compound $[E].$ The $IUPAC$ name of compound $[E]$ is $:$

What is the major product formed when salicylaldehyde is reacted with $2$ equivalents of bromine in glacial acetic acid at $0^{\circ} C$?

Benzaldehyde on heating with concentrated $NaOH$ gives:

The product of reduction of benzaldehyde is