The most commonly used solvent in C-13 NMR spectroscopy is ${\mathrm{CDCl}}_3$.

Given below are two statements:
Statement-I: Retardation factor $\left({\mathrm{R}}_{\mathrm{f}}\right)$ can be measured in meter/centimetre.

Statement-II: ${\mathrm{R}}_{\mathrm{f}}$ value of a compound remains constant in all solvents.

Choose the most appropriate answer from the options given below:

Using the provided information in the following paper chromatogram:

The calculated ${\mathrm{R}}_{\mathrm{f}}$ value of $\mathrm{A} \mathrm{is} \mathrm{\_\_\_\_\_}\times {10}^{-1}$.

What are the number of signals in ${}^1\mathrm{H} \mathrm{NMR}$ in the given molecules?