Answer:
The correct option is
A: Variety
Step-by-step explanation:
Variety is the principle of art that adds interest to an artwork. Using a range of different qualities or instances of an art element to create a desired visual effect. All harmony and no variety is boring. For performing the same task or following the same routine over and over again leads to boredom. That is why vacations are important and the same case applies to art as well.