从while循环PHP中获取单选按钮值

Question

我有一个包含四行的MySQL数据，每行代表一个问题和四个可能的答案。现在我想用四个答案显示每个问题作为单选按钮。我可以显示这些，但我很难在表单提交时获得用户选择的选项。

如何获取用户提交的值？

<?php 
include 'db.php';
if (!empty($_POST)) {
// get the id_question and its value

}
?>

<form action="" method="post" enctype="multipart/form-data">
<?php 

$sql ='select id_question, question,answer1,answer2,answer3,answer4 from prod_question_answers where id_product='.$_GET['id_product'];
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) { ?>

        <h1>
            <?php echo $row['question'] ?>
        </h1>

        <input name="<?php  echo $row['id_question'] ?>" type="radio"value="<?php echo $row['answer1'] ?>"><?php echo $row['answer1'] ?>
        <br> 
        <input name="<?php echo $row['id_question'] ?>" type="radio" value="<?php echo $row['answer2'] ?>"><?php echo $row['answer2'] ?>
        <br> 
        <input name="<?php echo $row['id_question'] ?>" type="radio" value="<?php echo $row['answer3'] ?>"><?php echo $row['answer3'] ?>
        <br> 
        <input name="<?php echo $row['id_question'] ?>" type="radio" value="<?php echo $row['answer4'] ?>"><?php echo $row['answer4'] ?>
        <?php   }
                       }
else {
     echo "0 results";
     }
     $conn->close();
 ?>
<button type="submit">Submit feedback</button>

</form>