[Plugin: Fast and Secure Contact Form] Multi-select Radio buttons?

If you need multi-select, use checkboxes.

Multi-Select (Checkbox) based questions allow users to choose more than one option for the same question. This is used when the intent of the question has a “select all that apply.”

Single-Select (Radio) based questions allow users only to choose one (and only one) option for any given question. This is used when the intent of the question is “select one.”

http://www.questionpro.com/help/76-inline.html