How to remove an admin option in Reading screen

Hi guys,

How can I remove the ‘Search Engine Visibility’ option from Reading Settings screen? I am currently running the following code in my theme’s functions.php:

function unregister_listed_settings() {
unregister_setting(‘reading’, ‘blog_public’);
}
add_action(‘init’, ‘unregister_listed_settings’);

but I get the following error:

Fatal error: Call to undefined function unregister_setting() in E:\wamp\www\dev01\wp-content\themes\skeleton\functions.php on line 43

Also, is there a list of all the existing $option_group and $option_name values because I have a feeling that I am providing the wrong arguments to the unregister_setting() function.

Will be eternally grateful for the help ??

Thanks,

Josh