Since this assignment is asking for your personal opinion, you'll have to give some thought to the subject matter and draw your own conclusions about what you believe. To help you hone in on your answer, though, here are a few questions you might ask yourself.
• Is it more important for art to be significant to the people who make it or to the people who view or experience it?
• Does all great art have a message behind it?
• Does art without self-expression exist?
• Is all art meaningful? If so, does it become more meaningful if more people see or experience it? Less meaningful?
• Do you make art? Do you like art made by others? What do those experiences mean to you?
As you write, keep this in mind: you're being asked this particular question in this particular way because there is no single correct answer. This is a topic that has been hotly debated as long as people have been making art, and the value of this inquiry is as much in the discourse as in the answer itself. Instead of focusing on reaching objective truth, focus on making a strong case for your personal conclusions. Don't just explain what you believe the answer to be—explain why that's the answer you've chosen. This will help you finesse your writing to meet the high expectations your teacher has set for this assignment.