The correct answer is variety. Variety is the principle of art has lots of different shapes, colors, forms, textures which are done to make the entire work more interesting. Variety is a principle of design concerned with diversity or contrast. Diversification is achieved by using many different elements to enhance the interaction in a work of art.
Principle of arts refers to how an artist uses elements of techniques such as lines, color, form, shape, value, and texture to organize a work of art. Other principles of art include balance, rhythm, harmony, emphasis, gradation, and movement.