${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\underset{\text{ step-1 }}{\stackrel{{\mathrm{Cl}}_2}{⟶}} {\mathrm{CH}}_3\mathrm{CHO}\frac{3{\mathrm{Cl}}_2}{\text{ step-2 }}{\mathrm{Cl}}_3\mathrm{CCHO}\text{. }$

In the above reaction, the role of $C{l}_2$in step-1 and step-2 respectively.

Given data : It is given to identify the role of Chlorine in the below chemical reaction.

Explanation 

 ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}\underset{\text{ step-1 }}{\stackrel{{\mathrm{Cl}}_2}{⟶}} {\mathrm{CH}}_3\mathrm{CHO}\frac{3{\mathrm{Cl}}_2}{\text{ step-2 }}{\mathrm{Cl}}_3\mathrm{CCHO}\text{. }$
As we know $C{H}_{3}C{H}_{2}OH$ is an Alcohol, and it is converted to $C{H}_{3}CHO$, which is an aldehyde, and we know that the conversion of alcohol to aldehyde is oxidation. Conversion of $C{H}_{3}CHO$(Aldehyde) to $C{l}_{3}CCHO$ Is chlorination because $3 H$is replaced by Cl.

Hence, the correct option (A). Oxidation and chlorination