B. sorting? because sorting is grouping
Art is used as a form of expression. Greek artists included the ideas of reason, moderation, balance, and harmony, because it was what they believed in. The Greeks often glorified the idea of being useful, peaceful, and living in simplicity, which would explain why their art work was influenced by it.
Picture plane is in perspective, the imaginary plane corresponding to the surface of a picture, perpendicular to the viewer's line of sight.