Final answer:
A request to a database for specific data related to certain words or phrases is known as a search query. The correct term for this in the given options is 'Search String'.
Step-by-step explanation:
A request that instructs an information service to look through a specific database for the occurrence of certain words and combinations of words is called a search query. When working with databases or search engines, this type of request is essential for retrieving the information you need.
The correct choice in the provided options would be Search String (D). Although other options may seem similar, the term "search string" specifically refers to the input of words and phrases used to tell the search engine or database what to look for.