Right option is (d) 3 times 1 surface area, both sides
The explanation: In Italy it is one of the most common and appreciated decorative plaster. We are talking about the Venetian plaster. The polished and coloured surface is a tradition since ancient Roman times, pozzolona dust is used, that is a sand of volcanic origin and it is responsible for making the surface polished and smooth, but you can also use marble dust or coloured pigments of quartz mixed with lime. History tells that this technique was improved during the Seventeenth and Eighteenth centuries in Venice, that is the reason why it is called “Venetian”, also called Roman plaster.
The more layers of Venetian plaster are applied, the more polished and extremely refined is the wall. Obviously it also more expensive because of the labor it needs.