Final answer:
When you save a document, you are creating a file. The correct answer is b.
Step-by-step explanation:
When you save a document, you are creating a file. This is the correct answer to the multiple-choice question, where the other options presented are link, key, and library entry. A file is a digital object that stores data, information, settings, or commands used by a computer program.
For example, when you write a report in a word processor and save it, the document is saved as a file on your computer's storage device. Files can have various formats depending on their content, such as .docx for Word documents or .pdf for Portable Document Format files. This file can then be retrieved, modified, or deleted at a later time. Hence the correct option is b.