Answer:
Criterion: A criterion is a certain requirement that someone must meet in order to qualify for something. (Judging, evaluating, or selecting something.)
Answer:
If you want to be a dj you can take a bachelor degree from sound or audio engineering which will take you four years but if you want to learn by yourself as a hobby it mostly depends on you if you are a fast learner or a slow learner you could find some courses online for free.
hope this helps.
David Hockney!! He creates portraits and landscapes mostly on ipads