Answer : 4. "उपरोक्त सभी"
Explanation :

The search engine performs the following tasks-

1. Web crawling: Search engines search all web pages on the web using a crawler. A crawler is a program that finds new web pages by following links on the web.

2. Indexing: Once the crawler finds all the web pages, the search engine indexes them in a database. The index contains information for each web page, such as title, URL, and content.

3. Searching: When a user types a search query, the search engine searches all the web pages in the index that may be related to the query.