In "fair use" cases courts are to look at four factors that should be considered but the list is not intended to be exhaustive. These four factors are:

1. The purpose and character of the use, including whether such use is of a commercial nature or is for nonprofit educational purposes

2. The nature of the copyrighted work

3. The amount and substantiality of the portion used in relation to the copyrighted work as a whole and

4. The effect of the use upon the potential market for or value of the copyrighted work.

How did he court apply fair use in the case of Sony BMG Music Entertainment v. Tenenbaum? Why was this case important? What were the defenses argued by Tennebaum and the Court's opinion of those defenses?