if I just have one radio button...Once clicked, it will stay clicked unless another input control of the same name attribute is selected. That's just the way radio buttons work. Checkboxes can be checked and unchecked.
... or just use a checkbox, if the checkbox behavior is what you want.The OP lists code with 3 radio buttons which by definition are mutually exclusive. To use a check box would mean writing JavaScript to make the checkboxes mutually exclusive - which is possible - you can see more in this PAQ (https://www.experts-exchange.com/questions/28978627/Mutually-exclusive-checkbox-in-a-gridview.html?anchorAnswerId=41864155#a41864155)
More explanation and ideas here:
https://www.experts-exchange.com/articles/5450/Common-Sense-Examples-Using-Checkboxes-with-HTML-JavaScript-and-PHP.html