set featured image option not displaying

add_theme_support( 'menus' );
add_theme_support( 'post-thumbnails' );

function register_theme_menus() {

    register_nav_menus(
        array(
            'primary-menu' =>__( 'Primary Menu' )
            )
        );

}
add_action( 'init', 'register_theme_menus' );

function wpt_theme_styles() {

    wp_enqueue_style( 'foundation_css', get_template_directory_uri() . '/css/foundation.css' );

    wp_enqueue_style( 'normalize_css', get_template_directory_uri() . '/css/normalize.' );

    wp_enqueue_style( 'googlefont_css', 'http://fonts.googleapis.com/css?family=Asap:400,700,400italic,700italic' );

    wp_enqueue_style( 'main_css', get_template_directory_uri() . '/style.css' );

}
    add_action( 'wp_enqueue_scripts', 'wpt_theme_styles');

    function wpt_theme_js() {

        wp_enqueue_script( 'modernizr_js', get_template_directory_uri() . '/js/modernizr.js','','', false);
        wp_enqueue_script( 'foundation_js', get_template_directory_uri() . '/js/foundation.min.js' ,array('jquery'),'', true);
        wp_enqueue_script( 'main_js', get_template_directory_uri() . '/js/app.js' ,array('jquery'),'',true );

    }

    add_action( 'wp_enqueue_scripts', 'wpt_theme_js');
?>```