How to Hide the "Business Hours Indicator" Admin Menu

function plt_hide_business_hours_indicator_menus() {
	//Hide the "Settings → Business Hours Indicator" menu.
	remove_submenu_page('options-general.php', 'business-hours-indicator');
}

add_action('admin_menu', 'plt_hide_business_hours_indicator_menus', 11);

Where do I put this code?