Cyclohexylamine when treated with nitrous acid yields $(\mathrm{P})$. On treating $(\mathrm{P})$ with $\mathrm{PCC}$ results in (Q). When $(\mathrm{Q})$ is heated with dil. $\mathrm{NaOH}$ we get $(\mathrm{R})$ The final product (R) is :

Consider the following reaction

The correct statement for product B is. It is

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: can be easily reduced using $\mathrm{Zn}-\mathrm{Hg} / \mathrm{HCl}$ to

Reason $\mathrm{R}: \mathrm{Zn}-\mathrm{Hg} / \mathrm{HCl}$ is used to reduce carbonyl group to $-\mathrm{CH}_{2}-$ group.

In the light of the above statements, choose the correct answer from the options given below:

What is the correct order of acidity of the protons marked $$\mathrm{A}-\mathrm{D}$$ in the given compounds ?