How to register a menu based on a ACF condition

Ok, so the problem was that I was adding the variable outside the function. After some cleanup, code looks like this and it works!

function roots_setup() {

// Variables

$header_type = get_field('header_type','options');

if (($header_type)=='brand-centered') {

register_nav_menus(array(
'brand_centered_left' => __('Brand Centered Navigation (Left)', 'roots')
));  

register_nav_menus(array(
'brand_centered_right' => __('Brand Centered Navigation (Right)', 'roots')
));  

} else {

register_nav_menus(array(
'primary_navigation' => __('Primary Navigation', 'roots')
));

}