I want to save cpt name in setting’s page options. I have the cpt list in select dropdown. I am not sure how to save the selected option.

Below is the code that displays the cpt list. Can anyone guide me? how do I save the selected option?

function ctp_settings_page()
{


    add_settings_section("section", null, null, "cpt");
    add_settings_field("cpt-select", "Select CPT", "cpt_checkbox_display", "cpt", "section");  
    register_setting("section", "cpt-select");
}


function cpt_checkbox_display()
{
?>
<?php
    
    $post_types = get_post_types(array('public' => true,  '_builtin' => false ), 'names', 'and');
    ?>
    <select class="" name="cpt-select">
    <?php

    foreach ($post_types  as $post_type) {
    ?>
        <option value="<?php echo esc_attr($post_type); ?>"><?php echo esc_html($post_type); ?></option>
    <?php
    }
    ?>
    </select>
    <?php
}
add_action("admin_init", "ctp_settings_page");