Lightbox problem in secondary menu

Using Enfold, I created a secondary menu with three custom links in it. I need the third one to open in a lightbox. Example:

Phone number (custom link): links to tel:1234567890
Apply (custom link): links to external site ex: google.com
Request (custom link): Links to a page : /request-information?iframe=true

I’ve then added this to the child-functions file:

// custom script
add_action( ‘wp_footer’, ‘ava_custom_script’ );
function ava_custom_script() {
?>
<script type=”text/javascript”>
(function($) {
function b() {
$(“#header_meta a”).magnificPopup({
type: ‘iframe’,
mainClass: ‘avia-popup mfp-zoom-in’,
});
}

$(window).load(function() {
b();
});

})(jQuery);
</script>
<?php
}

With this functions script added, it opens ALL three links in a lightbox. Without it, doesn’t open the third menu item in a lightbox.

Question: What is needed to make only the third button open in a lightbox?

Thanks in advance. You guys are the best.