Choose three statements referring to XML sitemaps that are true:

XML sitemaps are crucial for search engine crawlers to discover and index pages on your site. The statement "XML sitemaps must only contain URLs that give a HTTP 200 response" is correct because including URLs that return errors (like 404s or 500s) or redirects (301s, 302s) defeats the purpose of the sitemap and can waste crawl budget. The statement "XML sitemaps should usually be used when a website is very extensive" is correct as sitemaps are particularly beneficial for large sites, sites with isolated pages, or new sites, helping search engines find content they might otherwise miss. Finally, "It is recommended to use gzip compression and UTF-8 encoding" is correct because gzip compression reduces file size, making sitemaps faster to download for crawlers, and UTF-8 encoding ensures proper display of all characters. The incorrect options are false because you should not include non-200 status code URLs, and a website can have multiple XML sitemaps (e.g., sitemap indexes).