iTunes opens on my iMac automatically

iMac with OS X 10.11.5. iTunes opens with no prompting from me. I can close it all day and it keeps re-opening. I rarely want to use it. How to stop this from happening.

Thanks for the advice.

None of the suggestions here had made any difference. But, I kept looking and scouring the web and found (I don't remember where) what I thought, at first, was a half-assed suggestion that seems to have done the job. The suggestion was that a "dirty" or misaligned speaker jack could be the issue. Well, some days ago I removed the speaker plug from the iMac and, lo and behold, the constant opening of iTunes ceased. I will eventually experiment to see if that was really the issue, but at least temporarily I'm satisfied with using the internal speakers.