Option c is the correct answer. The Gandhara School of Art was a Greco-Buddhist schcol of art that flourished in the Gandhara region (now in Pakistan and Afghanistan) from the 1st to the 5th centuries CE. The school's sculptors initially used blue schist and green phyllite, but by the 3rd century CE, stucco had completely replaced stone as the main material used for sculptures. Important Tips Stucco: Stucco is a type of plaster that is made from lime, sand, and water. It is a relatively soft material, but it can be hardened by exposure to air. Stucco was a popular material for sculpture in the ancient world, and it was used by many different cultures, including the Greeks, Romans, and Egyptians. The use of stucco in the Gandhara School of Art had a significant impact on the style of the school's sculptures. Stucco is a more malleable material than stone, and this allowed the sculptors to create more realistic and expressive figures. The use of stucco also made it possible to paint and gild the sculptures, which added to their beauty and visual appeal.