Marcel duchamp, one of the dada artists of the early 20th century, drew a moustache on a cheap print of which famous painting.

The Mona Lisa

Explanation:

Marcel Duchamp, a French artist in the early 20th century, known for his breaking the boundaries between works of art and everyday objects. His works based on visual art. He drew mustache and beard on a small cheap postcard of the Mona Lisa with a pencil. His is quite familiar with his work on readymades, where he changes or add something new as he did in the Mona Lisa by adding beard and mustache and give it a new name.  

i think the answer is disc jockeys