Dropbox asking me to sign in to the app every time I get on my computer - How can I remove it?

[ReallyAnnoyedWithDragon]

Every time I turn on my Mac, this drop box sign in prompt appears (second image below), and there is also a drop box logo in the menu bar on the top right corner of my screen (black strip, first icon in pic below). I never did anything to make this happen, and I cannot get rid of it. 

I have an old drop box account that I never use. I have no idea how this happened, and have no need for this to appear every time I turn on my computer.

I feel hijacked by drop box and I'm really annoyed. Because I don't have a paid plan I can't get any direct help of any kind from drop box. This is really bad and really wrong. I have their stuff on my computer that I can't get rid of and there is no way to ask them for help! 

Can someone please help me get rid of this? I'd be SO grateful. Thank you so much. 🙏

[Rich]

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@Sarahltc wrote:

I don't have a 'Quit' option. Would 'Log out' be the same?

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No, it's not the same. Please provide a screenshot of what you're seeing, being sure to mask any private information.