Which principle of design would an artist consider if she wanted to add diverse shape, colors, or textures to make her artwork interesting to viewers?

Variety

explanation:

An artist would consider the VARIETY principle of design if she wanted to add diverse shape, colors, or textures to make her artwork interesting to viewers

including the octave, the answer would 8 notes in a major scale with one note being played twice. ex) c major scale includes: c, d, e, f, g, a, b, c

notice that c is played twice

however, if you were to ask me how many different notes are in a major scale- the answer would be 7.