解析错误：PHP中的语法错误，mysql数据库连接？

Question

意外＆＃39;如果＆＃39; （T_IF）在第19行的C：\ xampp \ htdocs \ forms \ insert1.php中。第19行是if（！mysqli_query（$ con，$ query））。请帮帮我？

   <?php
    $con=mysqli_connect("localhost","root","", CSF);

    if(mysqli_connect_errno()){
    echo "Connection Failed".mysqli_connect_errno();
    }
    else{
    echo"connected";}
    if (isset($_POST['submit']))
    {
        $LastName   = $_POST['LastName'];
        $FirstName  = $_POST['FirstName'];
        $MiddleName = $_POST['MiddleName'];
        $email      = $_POST['email'];
        $query="INSERT INTO Info(FirstName, MiddleName, LastName, email)
    VALUES($FirstName, $MiddleName, $LastName, $email)";

     
    if (!mysqli_query($con,$query))
     {
      die('Error: ' . mysqli_error($con));
      }

    echo "1 record added";
     
    mysql_close($con);
     }
    ?>