How to delete an answer for a radio button question for a specific respondent

When I use SG’s Response Editor function to change an answer, usually that works pretty well.  However, I want to delete an answer for a radio button question, not just change it.

I have tried sgapiListReplace with “” as the value being written to a certain question for a specific respondent, but that doesn’t seem to change the answer to null or no value (it seems to have no affect).  I have used sgapiListReplace enough successfully to know I have the correct syntax.

How would you go about deleting an answer for a specific question for a specific respondent in a radio button question?

Thank you.