Artists will often add which principle of design to provide interest in liven the unity of a work art

Variety.

Artists will often add variety to show something that will be different and eye catching to make people look at the piece for a while since there can be many elements, styles, textures, colors, and etc. involved.

Variety

they use this to catch the eye of people and it different. i could be the style, paint, color, texture, pretty much anything

Iwant to say it might be a or c my friend

Answerthe third and fourth;