Which type of solvent is added to an aqueous solution in the differential extraction method?

From the figure of column chromatography given below,identify the incorrect statements.
$A.$ Compound '$c$' is more polar than '$a$' and '$b$'
$B.$ Compound '$a$' is least polar
$C.$ Compound '$b$' comes out of the column before '$c$' and after '$a$'
$D.$ Compound '$a$' spends more time in the column
Choose the correct answer from the options given below :-

Explain partition chromatography. What is partition chromatography? Describe paper chromatography.

Which one of the following can be purified by sublimation?

Ethylene has a high $b.p.$ and high vapour pressure at $100\,^{\circ}C$ and does not dissolve in water. Hence,ethylene is separated by this method:

When the $TLC$ solvent reaches a height of $10 \, cm$,compound $(A)$ reaches $8 \, cm$ and compound $(B)$ reaches $6 \, cm$. Calculate the $R_f$ values of $(A)$ and $(B)$.