Front end entry form drop down field
I think you just need to get rid of the [] on the field name, so your field becomes:

&lt;input type="hidden" name="fields[questionStatus]" value="answered"&gt;


As long as the value is the same as the value in the dropdown, it should change.

I think the issue you are getting is because you are telling the field that its value is an array, where you just need to pass the actual value as a string and Craft will figure out the rest :)