Parent pages only

I created a metabox:

function mymetabox( $meta_boxes ) {
	$prefix = '';

	$meta_boxes[] = array(
		'id' => 'relatepagebox',
		'title' => esc_html__( 'Related Pages', 'metabox-online-generator' ),
		'post_types' => array('post' ),
		'context' => 'advanced',
		'priority' => 'default',
		'autosave' => 'false',
		'fields' => array(
			array(
				'id' => $prefix . 'relatepage',
				'type' => 'post',
				'name' => esc_html__( 'Related Pages', 'metabox-online-generator' ),
				'post_type' => 'page',
				'field_type' => 'select_advanced',
				'query_args' => array(),
				'attributes' => array(),
				'clone' => 'true',
				'sort_clone' => 'true',
			),
		),
	);

	return $meta_boxes;
}
add_filter( 'rwmb_meta_boxes', 'mymetabox' );

How to display only parent pages in select_advanced list?