Get WordPress administrator email from an external PHP script

gistfile1.php

<?php
// Load WordPress
require_once('../../../../wp-load.php');

$this_form_spam = trim($_POST['this_title']);

if ( empty($this_form_spam) ) {
    // Get values from form
    $name    = $_POST['name'];
    $phone   = $_POST['phone'];
    $email   = $_POST['email'];
    $message = $_POST['message'];
    
    $to = get_option('admin_email');

    $subject = 'Potential Client Lead';

    $message = " Name: $name\r\n Phone: $phone \r\n Email: $email \r\n Message: $message";

    $from = "FirmFlip";

    $headers = "From: $email\r\n";

    $headers .= "Content-type: text/plain; charset=UTF-8\r\n";

    if(@mail($to, $subject, $message, $headers)) {
        header('Location: /thanks/'); // Use header for redirections
    } else {
        echo 'Error! Please try again.';
    }
} else {
    // @TODO:
}