Sending documents for signatures via Dropbox

I am using the free plan. When sending documents for signatures, I use the checkboxes because we want to have our clients select options on the document, for example, "apples" or "oranges".  But, unfortunately, using the checkboxes made them select both apples and oranges. Is there a way to change it to one of the selections?

Also, I am using selections, where the client must select three sets out of six options. For example, select "apples" or "oranges"; "coffee" or "tea"; and "soup" or "salad".

Any help using the check boxes will help.

Thank you.