$servername = "localhost";
$username = "root";
$password = "";
$dbname = "names";

<div>
         <?php
        $conn = new mysqli($servername, $username, $password, $dbname);
        if ($conn->connect_error) {
        die("Connection failed: " . $conn->connect_error);
        }
        $sql = "SELECT * FROM surnames";
        $result = $conn->query($sql);

        if ($result->num_rows > 0) {
            echo "surnames ID : ";
            echo "<select name='surnamesoption' id='surnamesoption' >";
            while($row = mysqli_fetch_array( $result )) {
                echo '<option value = "'. $row['ID'] . '">' . $row['surnames'] . '</option>';
            }
            echo "</select>";
        }
        ?>
    </div>
<?php
    echo ** the sub string data of the option that is selected**
?>