Art is often controversial because

a.

artists use the elements of art in creative ways, which often offend the public.

b.

art is almost always based on religious beliefs or cultural circumstances.

c.

artists and observers have varying ideas of what art is.

d.

art is no longer a respected profession

Art is often controversial because artists and observers have varying ideas of what art is. The correct option among all the options that are given in the question is the third option or option "c". People might think about the art from a totally different angle than the artist who created it. I hope the answer helped you.