怎么知道前台页面选择了哪个选项？

后台页面的代码：
  //第二列
                    td = new TableCell();
                    td.Width = 620;
                    td.HorizontalAlign = HorizontalAlign.Left;
                    //判断题型
                    if (temp.T_ExeTestType == 1)
                    {
                        //该题为选择题                        
                        td.Controls.Add(new LiteralControl("<div style='margin-left:10px'>"+
                            "<input name=" +temp.T_ExeTestID + " type='radio' value='A' />" + "A、"+temp.T_ChoiceA +
                            "<br />" +
                            "<input name=" + temp.T_ExeTestID + " type='radio' value='B' />" + "B、"+temp.T_ChoiceB +
                            "<br />" +
                            "<input name=" + temp.T_ExeTestID + " type='radio' value='C' />" + "C、" + temp.T_ChoiceC +
                            "<br />" +
                            "<input name=" + temp.T_ExeTestID + " type='radio' value='D' />" + "D、" + temp.T_ChoiceD +
                            "<br /></div>"));
                    }
                    else if (temp.T_ExeTestType == 2)
                    {
                        //该题为判断题
                        td.Controls.Add(new LiteralControl("<div style='margin-left:10px'><input name=" +
                            temp.T_ExeTestID + " type='radio' value='A' />" + "对" +
                            "<br />"+
                            "<input name=" + temp.T_ExeTestID + " type='radio' value='B' />" + "错" +
                            "<br /></div>"));                    }
                    tr.Cells.Add(td);
                    //第三列
                    td = new TableCell();
                    td.Width = 100;
                    td.HorizontalAlign = HorizontalAlign.Center;
                    tr.Cells.Add(td);
                    //添加新行
                    Exercise_List.Rows.Add(tr);                }
前台还有个button按钮，我想按button按钮就把用户提交的答案存到数据库，但是不知道怎么获取用户选择了那个选项。刚学C#，大家多指教！inputbuttonradioc#