Consider not having a "None of the above option" and instead just putting a
*tip: if none of the options apply, leave them all unchecked.
In other words, "None of the above" is already represented very naturally by them simply not checking any options listed.
Or if you include it and people select more than one then you could exclude them from the dataset for low quality. e.g.
*question: Pick things
None of these
*if: ("None of these" in things) and (things.size > 1)
>> low_quality = 1