How to Hide the "Stop Registration Spam" Admin Menu

function plt_hide_stop_registration_spam_menus() {
	//Hide the "Settings → Stop Registration Spam" menu.
	remove_submenu_page('options-general.php', 'stop_registration_spam_options');
}

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

Where do I put this code?