从MySQL检索后如何使用PHP查看REST API

Question

I retrieved REST API from MySQL but look appears disgusting in Postman and uncomfortable for the following use.

I just begin to study PHP and can to a little bit.

My code:

<?php   
$connect = mysqli_connect("localhost", "***", "***", "***");

$sql = "SELECT `id_question`, `question`, `opt_asnwer_1`, `opt_asnwer_2`, `opt_asnwer_3`, `opt_asnwer_4`, `right_answer` FROM `questions`";
$result = mysqli_query($connect, $sql);
$json_array = array();

while($row = mysqli_fetch_assoc($result))
    {
        $json_array[] = $row;
    }
echo json_encode($json_array);

?>  

What look which I want to make. Example:

Please help me.