wp customizer api dropdown-pages

I am trying to use a dropdown page control to select a page but it is not working. With others control it works perfect.

functions.php

//section
$wp_customize->add_section('themename_color_scheme', array(
    'title'    => __('Color Scheme', 'themename'),
    'description' => '',
    'priority' => 120,
));
//setting
$wp_customize->add_setting('landing1', array(
        'capability'     => 'edit_theme_options',
        'type'           => 'option',

    ));
//control
$wp_customize->add_control('ld', array(
        'label'      => 'Front page section 1',
        'section'    => 'themename_color_scheme',
        'type'    => 'dropdown-pages',
        'settings'   => 'landing1',
));

page:

//trying to show the data (not working :/  )
$mod = get_theme_mod( 'ld');
echo($mod);
echo var_dump($mod);

echo ($mod) dont show anything and var_dump show “boolean false”