Which of John Cage's works is perceived by some to be a gimmick? A. Illiac Suite B. Imaginary Landscape no. 4 C. Einstein on a Beach D. 4'33"

I believe the correct answer is D. 4'33''.

It refers to his composition which lasts for four minutes and 33 seconds. It is rather controversial because there is no music at all - John Cage performed this before his confused audience who didn't know what was going on. Cage wanted to show that any sound in nature could be considered music, even if no actual instrumental sounds are made. So Cage just sat in front of his audience, without making a sound for 4 minutes and 33 seconds.