Answer:
What an author hopes to accomplish: <em>Purpose</em>
The author's attitude toward the subject: <em>Tone</em>
The author of a document and the author's background: <em>Individual</em>
Who a document is written for: <em>Audience</em>
The time, place, and circumstances surrounding a document: <em>Situation</em>
The main point or idea: <em>Message</em>
Explanation:
The "individual" refers to the author of a document and the author's background. This author will write a text for a particular group of people, which would be the "audience." The text will have a certain "tone," or attitude reflected in it, and this will most likely depend on the "message," or main point or idea of the text, and the "purpose," or what the author wants to accomplish. Finally, the time, place and other circumstances that surround a document would be the "situation."