<?php
// die when the file is called directly
if (!defined('WP_UNINSTALL_PLUGIN')) {
    die;
}
//define a vairbale and store an option name as the value.
$option_name = 'telegram_notify_option_name';
//call delete option and use the vairable inside the quotations
delete_option($option_name);
// for site options in Multisite
delete_site_option($option_name);
?>