Os pongo como el ejemplo de como esta echo...
Código html:
Ver original
<form name="answer"> <input type="radio" name="answer[a]">valor1 <input type="radio" name="answer[a]">valor2 <input type="radio" name="answer[a]">valor3 <input type="radio" name="answer[a]">valor4 <input type="radio" name="answer[b]">valor1 <input type="radio" name="answer[b]">valor2 <input type="radio" name="answer[b]">valor3 <input type="radio" name="answer[b]">valor4 <input type="radio" name="answer[c]">valor1 <input type="radio" name="answer[c]">valor2 <input type="radio" name="answer[c]">valor3 <input type="radio" name="answer[c]">valor4 <!-- y asi ontinuando --> </form>